Fix: Frequent Subscriptions problem that make Excessive CPU usage.

Thanks to mfshiu ! Closes #1096, Closes wekan/wekan-mongodb#2

client/components/boards/boardsList.js

@@ -1,6 +1,13 @@
 const subManager = new SubsManager();
 
 BlazeComponent.extendComponent({
+  onCreated() {
+    // Here is the only place that boards data needed, all boards data will stop sync when leaving this template.
+    Meteor.subscribe('boards');
+    Meteor.subscribe('setting');
+    Meteor.subscribe('user-admin');
+  },
+
   boards() {
     return Boards.find({
       archived: false,