Add documentation about protected branches.

doc/permissions/permissions.md

@@ -29,6 +29,7 @@ If a user is a GitLab administrator they receive all permissions.
 | Add new team members                  |         |            |             | ✓        | ✓      |
 | Push to protected branches            |         |            |             | ✓        | ✓      |
 | Enable/disable branch protection      |         |            |             | ✓        | ✓      |
+| Turn on/off prot. branch push for devs|         |            |             | ✓        | ✓      |
 | Rewrite/remove git tags               |         |            |             | ✓        | ✓      |
 | Edit project                          |         |            |             | ✓        | ✓      |
 | Add deploy keys to project            |         |            |             | ✓        | ✓      |

doc/workflow/README.md

@@ -8,3 +8,4 @@
 - [GitLab Flow](gitlab_flow.md)
 - [Notifications](notifications.md)
 - [Migrating from SVN to GitLab](migrating_from_svn.md)
+- [Protected branches](protected_branches.md)

doc/workflow/protected_branches.md

+# Protected branches
+
+Permission in GitLab are fundamentally defined around the idea of having read or write permission to the repository and branches.
+
+To prevent people from messing with history or pushing code without review, we've created protected branches.
+
+A protected branch does three simple things:
+
+* it prevents pushes from everybody except users with Master permission
+* it prevents anyone from force pushing to the branch
+* it prevents anyone from deleting the branch
+
+You can make any branch a protected branch. GitLab makes the master branch a protected branch by default.
+
+To protect a branch, user needs to have at least a Master permission level, see [permissions document](permissions/permissions.md).
+
+![protected branches page](protected_branches/protected_branches1.png)
+
+Navigate to project settings page and select `protected branches`. From the `Branch` dropdown menu select the branch you want to protect.
+
+Some workflows, like [GitLab workflow](gitlab_flow.md), require all users with write access to submit a Merge request in order to get the code into a protected branch.
+
+Since Masters and Owners can already push to protected branches, that means Developers cannot push to protected branch and need to submit a Merge request.
+
+However, there are workflows where that is not needed and only protecting from force pushes and branch removal is useful.
+
+For those workflows, you can allow everyone with write access to push to a protected branch by selecting `Developers can push` check box.
+
+On already protected branches you can also allow developers to push to the repository by selecting the `Developers can push` check box.
+
+![Developers can push](protected_branches/protected_branches2.png)
+
+