add user_id to expert
remove names from expert
add authors to user
add user to expert form
add admin/users functionality
some fixes in admin/users
fix user expert form
Merge branch 'feature/user_expert' into develop

* feature/user_expert:
  fix user expert form
  some fixes in admin/users
  add admin/users functionality
  add user to expert form
  add authors to user
  remove names from expert
  add user_id to expert