Add membership_lock to allowed params. Change settings page warning.

app/controllers/groups_controller.rb

@@ -163,6 +163,6 @@ class GroupsController < ApplicationController
   end
 
   def group_params
-    params.require(:group).permit(:name, :description, :path, :avatar)
+    params.require(:group).permit(:name, :description, :path, :avatar, :membership_lock)
   end
 end

app/views/projects/team_members/index.html.haml

@@ -15,7 +15,7 @@
   %strong= link_to "here", help_page_path("permissions", "permissions"), class: "vlink"
   - if membership_locked?
     %span.pull-right
-      Adding new user to membership is disabled by a group setting
+      Managing user access is disabled at group level
 
 = render "team", members: @project_members
 - if @group