$ sudo apt-get remove libgit-ruby 

Uninstall libgit-ruby including dependent package

If you would like to remove libgit-ruby and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove libgit-ruby 

Use Purging libgit-ruby

If you use with purge options to libgit-ruby package all the configuration and dependent packages will be removed.

$ sudo apt-get purge libgit-ruby 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove libgit-ruby 

See Also,