Merge branch 'deprecate' into 'master'

Deprecate the gitlab_git gem

See merge request !134

README.md

 # GitLab Git
+## `Gitlab::Git` has been absorbed into the [main GitLab project](https://gitlab-com/gitlab-org/gitlab-ce), and the `gitlab_git` gem has been deprecated. See the [gitlab-ce issue](https://gitlab.com/gitlab-org/gitlab-ce/issues/24374) and [merge request](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8447) for more information.
+
 GitLab wrapper around git objects.
 [![build status](https://gitlab.com/gitlab-org/gitlab_git/badges/master/build.svg)](https://gitlab.com/gitlab-org/gitlab_git/commits/master)
@@ -40,7 +42,7 @@ GitLab Git used grit as main library in past. Now it uses rugged
     # Search for code
     repo.search_files('rspec', 'master')
     # [ <Gitlab::Git::BlobSnippet:0x000..>, <Gitlab::Git::BlobSnippet:0x000..>]
- 
+
     # Access to rugged repo object
     repo.rugged
@@ -127,7 +129,7 @@ In case it's needed to update https://gitlab.com/gitlab-org/gitlab-git-test with
        }
     }
-    # Create or update file in repository. 
+    # Create or update file in repository.
     # Returns sha of commit that did a change
     Gitlab::Git::Blob.commit(repository, commit_options)
@@ -204,7 +206,7 @@ In case it's needed to update https://gitlab.com/gitlab-org/gitlab-git-test with
     # Diff object
     diff = commit.diffs.first
- 
+
     diff.diff #  "--- a/Gemfile.lock\....."
     diff.new_path # => "Gemfile.lock",
     diff.old_path # => "Gemfile.lock",