Add rugged

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Add specs for Git::Branch and Git::Tag classes

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Add  Git::Branch and Git::Tag classes

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Switch tags and branches to use rugged

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
 Merge branch 'refs-over-rugged' into 'master'

Refs over Rugged