Update avatars.js

increase the maximum avatar size

models/avatars.js

@@ -1,7 +1,7 @@
 Avatars = new FS.Collection('avatars', {
   stores: [new FS.Store.GridFS('avatars')],
   filter: {
-    maxSize: 72000,
+    maxSize: 520000,
     allow: {
       contentTypes: ['image/*'],
     },