Small refactor and addition of CI permissions

doc/permissions/permissions.md

 # Permissions
 
-Users have different abilities depending on the access level they have in a particular group or project.
+Users have different abilities depending on the access level they have in a
+particular group or project. If a user is both in a group's project and the
+project itself, the highest permission level is used.
 
-If a user is both in a project group and in the project itself, the highest permission level is used.
+On public and internal projects the Guest role is not enforced. All users will
+be able to create issues, leave comments, and pull or download the project code.
 
-If a user is a GitLab administrator they receive all permissions.
-
-On public and internal projects the Guest role is not enforced.
-All users will be able to create issues, leave comments, and pull or download the project code.
+GitLab administrators receive all permissions.
 
 To add or import a user, you can follow the [project users and members
 documentation](../workflow/add-user/add-user.md).
 
 ## Project
 
+The following table depicts the various user permission levels in a project.
+
 | Action                                | Guest   | Reporter   | Developer   | Master   | Owner  |
 |---------------------------------------|---------|------------|-------------|----------|--------|
 | Create new issue                      | ✓       | ✓          | ✓           | ✓        | ✓      |
@@ -46,8 +48,8 @@ documentation](../workflow/add-user/add-user.md).
 | Add new team members                  |         |            |             | ✓        | ✓      |
 | Push to protected branches            |         |            |             | ✓        | ✓      |
 | Enable/disable branch protection      |         |            |             | ✓        | ✓      |
-| Turn on/off prot. branch push for devs|         |            |             | ✓        | ✓      |
-| Rewrite/remove git tags               |         |            |             | ✓        | ✓      |
+| Turn on/off protected branch push for devs|         |            |             | ✓        | ✓      |
+| Rewrite/remove Git tags               |         |            |             | ✓        | ✓      |
 | Edit project                          |         |            |             | ✓        | ✓      |
 | Add deploy keys to project            |         |            |             | ✓        | ✓      |
 | Configure project hooks               |         |            |             | ✓        | ✓      |
@@ -66,10 +68,9 @@ documentation](../workflow/add-user/add-user.md).
 
 ## Group
 
-In order for a group to appear as public and be browsable, it must contain at
-least one public project.
-
-Any user can remove themselves from a group, unless they are the last Owner of the group.
+Any user can remove themselves from a group, unless they are the last Owner of
+the group. The following table depicts the various user permission levels in a
+group.
 
 | Action                  | Guest | Reporter | Developer | Master | Owner |
 |-------------------------|-------|----------|-----------|--------|-------|
@@ -101,4 +102,30 @@ to **Admin > Users** to create a new user or edit an existing one. There, you
 will find the option to flag the user as external.
 
 By default new users are not set as external users. This behavior can be changed
-by an administrator under **Admin > Application Settings**.
\ No newline at end of file
+by an administrator under **Admin > Application Settings**.
+
+## GitLab CI
+
+GitLab CI permissions rely on the role the user has in GitLab. There are four
+permission levels it total:
+
+- admin
+- master
+- developer
+- guest/reporter
+
+The admin user can perform any action on GitLab CI in scope of the GitLab
+instance and project. In addition, all admins can use the admin interface under
+`/admin/runners`.
+
+| Action                                | Guest, Reporter | Developer   | Master   | Admin  |
+|---------------------------------------|-----------------|-------------|----------|--------|
+| See commits and builds                | ✓               | ✓           | ✓        | ✓      |
+| Retry or cancel build                 |                 | ✓           | ✓        | ✓      |
+| Remove project                        |                 |             | ✓        | ✓      |
+| Create project                        |                 |             | ✓        | ✓      |
+| Change project configuration          |                 |             | ✓        | ✓      |
+| Add specific runners                  |                 |             | ✓        | ✓      |
+| Add shared runners                    |                 |             |          | ✓      |
+| See events in the system              |                 |             |          | ✓      |
+| Admin interface                       |                 |             |          | ✓      |