Document the basics of working with Groups

doc/workflow/README.md

 - [Workflow](workflow.md)
 - [Project Features](project_features.md)
 - [Authorization for merge requests](authorization_for_merge_requests.md)
+- [Groups](groups.md)

doc/workflow/groups.md

+# GitLab Groups
+
+GitLab groups allow you to group projects into directories and give users to several projects at once.
+
+When you create a new project in GitLab, the default namespace for the project is the personal namespace associated with your GitLab user.
+In this document we will see how to create groups, put projects in groups and manage who can access the projects in a group.
+
+## Creating groups
+
+You can create a group by going to the 'Groups' tab of the GitLab dashboard and clicking the 'New group' button.
+
+![Click the 'New group' button in the 'Groups' tab](groups/new_group_button.png)
+
+Next, enter the name (required) and the optional description and group avatar.
+
+![Fill in the name for your new group](groups/new_group_form.png)
+
+When your group has been created you are presented with the group dashboard feed, which will be empty.
+
+![Group dashboard](groups/group_dashboard.png)
+
+You can use the 'New project' button to add a project to the new group.
+
+## Transfering an existing project into a group
+
+You can transfer an existing project into a group you own from the project settings page.
+First scroll down to the 'Dangerous settings' and click 'Show them to me'.
+Now you can pick any of the groups you manage as the new namespace for the group.
+
+![Transfer a project to a new namespace](groups/transfer_project.png)
+
+GitLab administrators can use the admin interface to move any project to any namespace if needed.
+
+## Adding users to a group
+
+One of the benefits of putting multiple projects in one group is that you can give a user to access to all projects in the group with one action.
+
+Suppose we have a group with two projects.
+
+![Group with two projects](groups/groups/group_with_two_projects.png)
+
+On the 'Group Members' page we can now add a new user Barry to the group.
+
+![Add user Barry to the group](groups/add_member_to_group.png)
+
+Now because Barry is a 'Developer' member of the 'Open Source' group, he automatically gets 'Developer' access to all projects in the 'Open Source' group.
+
+![Barry has 'Developer' access to GitLab CI](groups/project_members_via_group.png)
+
+If necessary, you can increase the access level of an individual user for a specific project, by adding them as a Member to the project.
+
+![Barry effectively has 'Master' access to GitLab CI now](groups/override_access_level.png)
+
+## Managing group memberships via LDAP
+
+In GitLab Enterprise Edition it is possible to manage GitLab group memberships using LDAP groups.
+See [the GitLab Enterprise Edition documentation](http://doc.gitlab.com/ee/integration/ldap.html) for more information.
+
+## Allowing only admins to create groups
+
+By default, any GitLab user can create new groups.
+This ability can be disabled for individual users from the admin panel. 
+It is also possible to configure GitLab so that new users default to not being able to create groups:
+
+```
+# For omnibus-gitlab, put the following in /etc/gitlab/gitlab.rb
+gitlab_rails['gitlab_default_can_create_group'] = false
+
+# For installations from source, uncomment the 'default_can_create_group'
+# line in /home/git/gitlab/config/gitlab.yml
+```