Merge branch 'fix-group-projects-sort' into 'master'

Projects on group page should be sorted by last activity instead of id/created_at
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fixes #15237 

See merge request !3716

app/controllers/groups_controller.rb

@@ -40,6 +40,7 @@ class GroupsController < Groups::ApplicationController
     @last_push = current_user.recent_push if current_user
 
     @projects = @projects.includes(:namespace)
+    @projects = @projects.sorted_by_activity
     @projects = filter_projects(@projects)
     @projects = @projects.sort(@sort = params[:sort])
     @projects = @projects.page(params[:page]) if params[:filter_projects].blank?