user group: sort lists of current and available members by username

It was hard to navigate lists with 200 users in "random" (user_id?) order.

rhodecode/controllers/admin/users_groups.py

@@ -130,11 +130,13 b' class UsersGroupsController(BaseControll'
             c.users_group.permissions['repositories_groups'][gr.group.group_name] \
                 = gr.permission.permission_name
 
-        c.group_members_obj = [x.user for x in c.users_group.members]
+        c.group_members_obj = sorted((x.user for x in c.users_group.members),
+                                     key=lambda u: u.username.lower())
         c.group_members = [(x.user_id, x.username) for x in
                            c.group_members_obj]
-        c.available_members = [(x.user_id, x.username) for x in
-                               User.query().all()]
+        c.available_members = sorted(((x.user_id, x.username) for x in
+                                      User.query().all()),
+                                     key=lambda u: u[1].lower())
 
     def update(self, id):
         """PUT /users_groups/id: Update an existing item"""

rhodecode/templates/admin/users_groups/users_group_edit.html

@@ -87,7 +87,7 b''
 
                 </div>
                 <div class="buttons">
-                  ${h.submit('save',_('save'),class_="ui-btn large")}
+                  ${h.submit('Save',_('save'),class_="ui-btn large")}
                 </div>
             </div>
     </div>