share with group documentation

doc/workflow/README.md

@@ -12,5 +12,6 @@
 - [Project importing from GitHub to GitLab](import_projects_from_github.md)
 - [Project importing from GitLab.com to your private GitLab instance](import_projects_from_gitlab_com.md)
 - [Protected branches](protected_branches.md)
+- [Sharing a project with a group](share_with_group.md)
 - [Web Editor](web_editor.md)
 - [Manage large binaries with git annex](git_annex.md)

doc/workflow/share_with_group.md

+# Sharing a project with a group
+
+If you want to share a single project in a group with another group,
+you can do so easily. By setting the permission you can quickly
+give a select group of users access to a project in a restricted manner.
+
+In a project go to the project settings -> groups.
+
+Now you can select a group that you want to share this project with and with
+which access level. Users in that group are able to access this project
+with the set access level.
+
+![Share a project with a group](share_with_group.png)