help: Add user-groups.

static/templates/user-groups-admin.handlebars

@@ -18,7 +18,7 @@
                     <input type="text" name="description" id="user_group_description" maxlength="300" placeholder="{{t 'Marketing team' }}" />
                 </div>
                 <button type="submit" class="button rounded sea-green">
-                    {{t 'Submit' }}
+                    {{t 'Save' }}
                 </button>
             </div>
         </div>

templates/zerver/help/include/sidebar_index.md

@@ -130,6 +130,7 @@
 ## Users & bots
 * [Invite new users](/help/invite-new-users)
 * [Allow anyone to join](/help/allow-anyone-to-join-without-an-invitation)
+* [User groups](/help/user-groups)
 * [Deactivate or reactivate a user](/help/deactivate-or-reactivate-a-user)
 * [Deactivate or reactivate a bot](/help/deactivate-or-reactivate-a-bot)
 * [Restrict bot creation](/help/restrict-bot-creation)

templates/zerver/help/mention-a-user-or-group.md

@@ -1,6 +1,6 @@
 # Mention a user or group
 
-You can mention a team member or user group to call their attention to a
+You can mention a team member or [user group](/help/user-groups) to call their attention to a
 message. Mentions follow the same
 [notification settings](/help/pm-mention-alert-notifications) as private
 messages and alert words.

templates/zerver/help/user-groups.md

@@ -0,0 +1,39 @@
+# User groups
+
+User groups allow you to [mention](/help/mention-a-user-or-group) multiple
+members at once. When you mention a user group, everyone in the group is
+[notified](/help/pm-mention-alert-notifications) as if they were
+individually mentioned.
+
+### Create a user group
+
+{start_tabs}
+
+{settings_tab|user-groups-admin}
+
+1. Under **Add a new user group**, enter a **Name** and **Description**.
+
+1. Click **Save**.
+
+1. Find the group in the list below, and add members. Zulip will notify
+   everyone who is added.
+
+{end_tabs}
+
+### Modify a user group
+
+Organization administrators can modify any user group. Members can modify
+any user group they are a part of.
+
+{start_tabs}
+
+{settings_tab|user-groups-admin}
+
+1. Find the group.
+
+1. Click on the group name or description to edit.
+
+1. Add or remove members (including yourself). Click outside the member box
+   to save.  Zulip will notify everyone who is added or removed.
+
+{end_tabs}