Merge branch 'fix_git_tag_in_architecture' into 'master'

Fixed ~git beeing displayed as link to issues tagged with git in architecture.md

The architecture documentation explains `~git` from the picture below which is replaced by a [link to issues tagged with `git`](https://gitlab.com/gitlab-org/gitlab-ce/issues?label_name=git). I believe that this was unintended and should be fixed by using backticks.

![Screenshot_from_2016-02-13_21-36-30](/uploads/5ea1a60e8b230952874e58eab0abe1ac/Screenshot_from_2016-02-13_21-36-30.png)

See merge request !2814

doc/development/architecture.md

@@ -42,7 +42,7 @@ Gitlab-shell communicates with Sidekiq via the “communication board” (Redis)
 
 ## System Layout
 
-When referring to ~git in the pictures it means the home directory of the git user which is typically /home/git.
+When referring to `~git` in the pictures it means the home directory of the git user which is typically /home/git.
 
 GitLab is primarily installed within the `/home/git` user home directory as `git` user. Within the home directory is where the gitlabhq server software resides as well as the repositories (though the repository location is configurable).