Merge pull request #1 from stupied4ever/refactor-pre-commits

Big scary rewrite
Add GitHooks.hook_installed?
Rename HookFile => ConfigFile
Move git_repository to Configurations
Add GitHooks.configurations=
Add Configurations#pre_commits
Fix hook_installed?
Fix configurations default file
Fix hook_installed?
hook.sample execute pre_commit hooks
Add GitHooks.execute_pre_commits
Fix pre commit hooks