Add author id to the right selector

app/assets/javascripts/users_select.js.coffee

@@ -12,6 +12,7 @@ class @UsersSelect
       showNullUser = $dropdown.data('null-user')
       showAnyUser = $dropdown.data('any-user')
       firstUser = $dropdown.data('first-user')
+      @authorId = $dropdown.data('author-id')
       selectedId = $dropdown.data('selected')
       defaultLabel = $dropdown.data('default-label')
       issueURL = $dropdown.data('issueUpdate')