Merge branch '164-console-error-when-deleting-a-group' into 'dev'

Resolve "console error when deleting a group"

Closes #164

See merge request !574

app/imports/ui/components/admin/GroupUsersList.jsx

@@ -251,8 +251,8 @@ GroupsUsersList.propTypes = {
 
 export default withTracker(({ groupId, userRole }) => {
   const subUsers = Meteor.subscribe('groups.users', { groupId, role: userRole });
-  const group = Groups.findOne(groupId);
-  const users = Meteor.users.find({}).fetch();
+  const group = Groups.findOne(groupId) || {};
+  const users = Meteor.users.find({}).fetch() || [];
   const ready = subUsers.ready();
   return {
     ready,