UK: accept team name to access a specific team, does not result in int ValueError exception
UK: use SlugRelatedField instead of HyperlinkedRelatedField for the organization
UK: Add user to a team via the API, closes #282
UK: refactor teams/members endpoint to list and members to a team
Merge branch 'master' into 282-add-user-to-team

* master:
  UK: docs for add user to organization
  UK: Add user to an orgnization via the API, closes #281
  UK: list members in an organization
  UK: get and create organization members team/group
PLD: shorter line for pep8
Merge pull request #291 from onaio/282-add-user-to-team

Add user to a team via the API