- Fix lint errors.

  Note: variable trackingUsers is not used anywhere, so it was removed.

Thanks to xet7 !

models/activities.js

@@ -151,7 +151,6 @@ if (Meteor.isServer) {
     }
     if (board) {
       const watchingUsers = _.pluck(_.where(board.watchers, {level: 'watching'}), 'userId');
-      const trackingUsers = _.pluck(_.where(board.watchers, {level: 'tracking'}), 'userId');
       watchers = _.union(watchers, watchingUsers || []);
     }
 

server/migrations.js

@@ -341,4 +341,4 @@ Migrations.add('remove-tag', () => {
       'profile.tags':1,
     },
   }, noValidateMulti);
-});
+});