func (s *RepositoriesService) GetBranch(owner, repo, branch string) (*Branch, *Response, error) {
	u := fmt.Sprintf("repos/%v/%v/branches/%v", owner, repo, branch)
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	req.Header.Set("Accept", mediaTypeProtectedBranchesPreview)
	b := new(Branch)
	resp, err := s.client.Do(req, b)
	if err != nil {
		return nil, resp, err
	}
	return b, resp, err
}
GetBranch gets the specified branch for a repository.

GitHub API docs: https://developer.github.com/v3/repos/#get-branch
package github
import (
	"fmt"
	"strings"
)
type RepositoriesService service
type Repository struct {
	ID               *int             `json:"id,omitempty"`
	Owner            *User            `json:"owner,omitempty"`
	Name             *string          `json:"name,omitempty"`
	FullName         *string          `json:"full_name,omitempty"`
	Description      *string          `json:"description,omitempty"`
	Homepage         *string          `json:"homepage,omitempty"`
	DefaultBranch    *string          `json:"default_branch,omitempty"`
	MasterBranch     *string          `json:"master_branch,omitempty"`
	CreatedAt        *Timestamp       `json:"created_at,omitempty"`
	PushedAt         *Timestamp       `json:"pushed_at,omitempty"`
	UpdatedAt        *Timestamp       `json:"updated_at,omitempty"`
	HTMLURL          *string          `json:"html_url,omitempty"`
	CloneURL         *string          `json:"clone_url,omitempty"`
	GitURL           *string          `json:"git_url,omitempty"`
	MirrorURL        *string          `json:"mirror_url,omitempty"`
	SSHURL           *string          `json:"ssh_url,omitempty"`
	SVNURL           *string          `json:"svn_url,omitempty"`
	Language         *string          `json:"language,omitempty"`
	Fork             *bool            `json:"fork"`
	ForksCount       *int             `json:"forks_count,omitempty"`
	NetworkCount     *int             `json:"network_count,omitempty"`
	OpenIssuesCount  *int             `json:"open_issues_count,omitempty"`
	StargazersCount  *int             `json:"stargazers_count,omitempty"`
	SubscribersCount *int             `json:"subscribers_count,omitempty"`
	WatchersCount    *int             `json:"watchers_count,omitempty"`
	Size             *int             `json:"size,omitempty"`
	AutoInit         *bool            `json:"auto_init,omitempty"`
	Parent           *Repository      `json:"parent,omitempty"`
	Source           *Repository      `json:"source,omitempty"`
	Organization     *Organization    `json:"organization,omitempty"`
	Permissions      *map[string]bool `json:"permissions,omitempty"`
	AllowRebaseMerge *bool            `json:"allow_rebase_merge,omitempty"`
	AllowSquashMerge *bool            `json:"allow_squash_merge,omitempty"`
	AllowMergeCommit *bool            `json:"allow_merge_commit,omitempty"`
	License *License `json:"license,omitempty"`
	Private           *bool   `json:"private"`
	HasIssues         *bool   `json:"has_issues"`
	HasWiki           *bool   `json:"has_wiki"`
	HasPages          *bool   `json:"has_pages"`
	HasDownloads      *bool   `json:"has_downloads"`
	LicenseTemplate   *string `json:"license_template,omitempty"`
	GitignoreTemplate *string `json:"gitignore_template,omitempty"`
	TeamID *int `json:"team_id"`
	URL              *string `json:"url,omitempty"`
	ArchiveURL       *string `json:"archive_url,omitempty"`
	AssigneesURL     *string `json:"assignees_url,omitempty"`
	BlobsURL         *string `json:"blobs_url,omitempty"`
	BranchesURL      *string `json:"branches_url,omitempty"`
	CollaboratorsURL *string `json:"collaborators_url,omitempty"`
	CommentsURL      *string `json:"comments_url,omitempty"`
	CommitsURL       *string `json:"commits_url,omitempty"`
	CompareURL       *string `json:"compare_url,omitempty"`
	ContentsURL      *string `json:"contents_url,omitempty"`
	ContributorsURL  *string `json:"contributors_url,omitempty"`
	DeploymentsURL   *string `json:"deployments_url,omitempty"`
	DownloadsURL     *string `json:"downloads_url,omitempty"`
	EventsURL        *string `json:"events_url,omitempty"`
	ForksURL         *string `json:"forks_url,omitempty"`
	GitCommitsURL    *string `json:"git_commits_url,omitempty"`
	GitRefsURL       *string `json:"git_refs_url,omitempty"`
	GitTagsURL       *string `json:"git_tags_url,omitempty"`
	HooksURL         *string `json:"hooks_url,omitempty"`
	IssueCommentURL  *string `json:"issue_comment_url,omitempty"`
	IssueEventsURL   *string `json:"issue_events_url,omitempty"`
	IssuesURL        *string `json:"issues_url,omitempty"`
	KeysURL          *string `json:"keys_url,omitempty"`
	LabelsURL        *string `json:"labels_url,omitempty"`
	LanguagesURL     *string `json:"languages_url,omitempty"`
	MergesURL        *string `json:"merges_url,omitempty"`
	MilestonesURL    *string `json:"milestones_url,omitempty"`
	NotificationsURL *string `json:"notifications_url,omitempty"`
	PullsURL         *string `json:"pulls_url,omitempty"`
	ReleasesURL      *string `json:"releases_url,omitempty"`
	StargazersURL    *string `json:"stargazers_url,omitempty"`
	StatusesURL      *string `json:"statuses_url,omitempty"`
	SubscribersURL   *string `json:"subscribers_url,omitempty"`
	SubscriptionURL  *string `json:"subscription_url,omitempty"`
	TagsURL          *string `json:"tags_url,omitempty"`
	TreesURL         *string `json:"trees_url,omitempty"`
	TeamsURL         *string `json:"teams_url,omitempty"`
	TextMatches []TextMatch `json:"text_matches,omitempty"`
}
func (r Repository) String() string {
	return Stringify(r)
}
type RepositoryListOptions struct {
	Visibility string `url:"visibility,omitempty"`
	Affiliation string `url:"affiliation,omitempty"`
	Type string `url:"type,omitempty"`
	Sort string `url:"sort,omitempty"`
	Direction string `url:"direction,omitempty"`
	ListOptions
}
func (s *RepositoriesService) List(user string, opt *RepositoryListOptions) ([]*Repository, *Response, error) {
	var u string
	if user != "" {
		u = fmt.Sprintf("users/%v/repos", user)
	} else {
		u = "user/repos"
	}
	u, err := addOptions(u, opt)
	if err != nil {
		return nil, nil, err
	}
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	req.Header.Set("Accept", mediaTypeLicensesPreview)
	repos := new([]*Repository)
	resp, err := s.client.Do(req, repos)
	if err != nil {
		return nil, resp, err
	}
	return *repos, resp, err
}
type RepositoryListByOrgOptions struct {
	Type string `url:"type,omitempty"`
	ListOptions
}
func (s *RepositoriesService) ListByOrg(org string, opt *RepositoryListByOrgOptions) ([]*Repository, *Response, error) {
	u := fmt.Sprintf("orgs/%v/repos", org)
	u, err := addOptions(u, opt)
	if err != nil {
		return nil, nil, err
	}
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	req.Header.Set("Accept", mediaTypeLicensesPreview)
	repos := new([]*Repository)
	resp, err := s.client.Do(req, repos)
	if err != nil {
		return nil, resp, err
	}
	return *repos, resp, err
}
type RepositoryListAllOptions struct {
	Since int `url:"since,omitempty"`
	ListOptions
}
func (s *RepositoriesService) ListAll(opt *RepositoryListAllOptions) ([]*Repository, *Response, error) {
	u, err := addOptions("repositories", opt)
	if err != nil {
		return nil, nil, err
	}
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	repos := new([]*Repository)
	resp, err := s.client.Do(req, repos)
	if err != nil {
		return nil, resp, err
	}
	return *repos, resp, err
}
func (s *RepositoriesService) Create(org string, repo *Repository) (*Repository, *Response, error) {
	var u string
	if org != "" {
		u = fmt.Sprintf("orgs/%v/repos", org)
	} else {
		u = "user/repos"
	}
	req, err := s.client.NewRequest("POST", u, repo)
	if err != nil {
		return nil, nil, err
	}
	r := new(Repository)
	resp, err := s.client.Do(req, r)
	if err != nil {
		return nil, resp, err
	}
	return r, resp, err
}
func (s *RepositoriesService) Get(owner, repo string) (*Repository, *Response, error) {
	u := fmt.Sprintf("repos/%v/%v", owner, repo)
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	acceptHeaders := []string{mediaTypeLicensesPreview, mediaTypeSquashPreview}
	req.Header.Set("Accept", strings.Join(acceptHeaders, ", "))
	repository := new(Repository)
	resp, err := s.client.Do(req, repository)
	if err != nil {
		return nil, resp, err
	}
	return repository, resp, err
}
func (s *RepositoriesService) GetByID(id int) (*Repository, *Response, error) {
	u := fmt.Sprintf("repositories/%d", id)
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	req.Header.Set("Accept", mediaTypeLicensesPreview)
	repository := new(Repository)
	resp, err := s.client.Do(req, repository)
	if err != nil {
		return nil, resp, err
	}
	return repository, resp, err
}
func (s *RepositoriesService) Edit(owner, repo string, repository *Repository) (*Repository, *Response, error) {
	u := fmt.Sprintf("repos/%v/%v", owner, repo)
	req, err := s.client.NewRequest("PATCH", u, repository)
	if err != nil {
		return nil, nil, err
	}
	req.Header.Add("Accept", mediaTypeSquashPreview)
	r := new(Repository)
	resp, err := s.client.Do(req, r)
	if err != nil {
		return nil, resp, err
	}
	return r, resp, err
}
func (s *RepositoriesService) Delete(owner, repo string) (*Response, error) {
	u := fmt.Sprintf("repos/%v/%v", owner, repo)
	req, err := s.client.NewRequest("DELETE", u, nil)
	if err != nil {
		return nil, err
	}
	return s.client.Do(req, nil)
}
type Contributor struct {
	Login             *string `json:"login,omitempty"`
	ID                *int    `json:"id,omitempty"`
	AvatarURL         *string `json:"avatar_url,omitempty"`
	GravatarID        *string `json:"gravatar_id,omitempty"`
	URL               *string `json:"url,omitempty"`
	HTMLURL           *string `json:"html_url,omitempty"`
	FollowersURL      *string `json:"followers_url,omitempty"`
	FollowingURL      *string `json:"following_url,omitempty"`
	GistsURL          *string `json:"gists_url,omitempty"`
	StarredURL        *string `json:"starred_url,omitempty"`
	SubscriptionsURL  *string `json:"subscriptions_url,omitempty"`
	OrganizationsURL  *string `json:"organizations_url,omitempty"`
	ReposURL          *string `json:"repos_url,omitempty"`
	EventsURL         *string `json:"events_url,omitempty"`
	ReceivedEventsURL *string `json:"received_events_url,omitempty"`
	Type              *string `json:"type,omitempty"`
	SiteAdmin         *bool   `json:"site_admin"`
	Contributions     *int    `json:"contributions,omitempty"`
}
type ListContributorsOptions struct {
	Anon string `url:"anon,omitempty"`
	ListOptions
}
func (s *RepositoriesService) ListContributors(owner string, repository string, opt *ListContributorsOptions) ([]*Contributor, *Response, error) {
	u := fmt.Sprintf("repos/%v/%v/contributors", owner, repository)
	u, err := addOptions(u, opt)
	if err != nil {
		return nil, nil, err
	}
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	contributor := new([]*Contributor)
	resp, err := s.client.Do(req, contributor)
	if err != nil {
		return nil, nil, err
	}
	return *contributor, resp, err
}
func (s *RepositoriesService) ListLanguages(owner string, repo string) (map[string]int, *Response, error) {
	u := fmt.Sprintf("repos/%v/%v/languages", owner, repo)
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	languages := make(map[string]int)
	resp, err := s.client.Do(req, &languages)
	if err != nil {
		return nil, resp, err
	}
	return languages, resp, err
}
func (s *RepositoriesService) ListTeams(owner string, repo string, opt *ListOptions) ([]*Team, *Response, error) {
	u := fmt.Sprintf("repos/%v/%v/teams", owner, repo)
	u, err := addOptions(u, opt)
	if err != nil {
		return nil, nil, err
	}
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	teams := new([]*Team)
	resp, err := s.client.Do(req, teams)
	if err != nil {
		return nil, resp, err
	}
	return *teams, resp, err
}
type RepositoryTag struct {
	Name       *string `json:"name,omitempty"`
	Commit     *Commit `json:"commit,omitempty"`
	ZipballURL *string `json:"zipball_url,omitempty"`
	TarballURL *string `json:"tarball_url,omitempty"`
}
func (s *RepositoriesService) ListTags(owner string, repo string, opt *ListOptions) ([]*RepositoryTag, *Response, error) {
	u := fmt.Sprintf("repos/%v/%v/tags", owner, repo)
	u, err := addOptions(u, opt)
	if err != nil {
		return nil, nil, err
	}
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	tags := new([]*RepositoryTag)
	resp, err := s.client.Do(req, tags)
	if err != nil {
		return nil, resp, err
	}
	return *tags, resp, err
}
type Branch struct {
	Name      *string           `json:"name,omitempty"`
	Commit    *RepositoryCommit `json:"commit,omitempty"`
	Protected *bool             `json:"protected,omitempty"`
}
type Protection struct {
	RequiredStatusChecks       *RequiredStatusChecks       `json:"required_status_checks"`
	RequiredPullRequestReviews *RequiredPullRequestReviews `json:"required_pull_request_reviews"`
	Restrictions               *BranchRestrictions         `json:"restrictions"`
}
type ProtectionRequest struct {
	RequiredStatusChecks       *RequiredStatusChecks       `json:"required_status_checks"`
	RequiredPullRequestReviews *RequiredPullRequestReviews `json:"required_pull_request_reviews"`
	Restrictions               *BranchRestrictionsRequest  `json:"restrictions"`
}
type RequiredStatusChecks struct {
	IncludeAdmins bool `json:"include_admins"`
	Strict bool `json:"strict"`
	Contexts []string `json:"contexts"`
}
type RequiredPullRequestReviews struct {
	IncludeAdmins bool `json:"include_admins"`
}
type BranchRestrictions struct {
	Users []*User `json:"users"`
	Teams []*Team `json:"teams"`
}
type BranchRestrictionsRequest struct {
	Users []string `json:"users"`
	Teams []string `json:"teams"`
}
func (s *RepositoriesService) ListBranches(owner string, repo string, opt *ListOptions) ([]*Branch, *Response, error) {
	u := fmt.Sprintf("repos/%v/%v/branches", owner, repo)
	u, err := addOptions(u, opt)
	if err != nil {
		return nil, nil, err
	}
	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return nil, nil, err
	}
	req.Header.Set("Accept", mediaTypeProtectedBranchesPreview)
	branches := new([]*Branch)
	resp, err := s.client.Do(req, branches)
	if err != nil {
		return nil, resp, err
	}
	return *branches, resp, err
}