Use POST instead of GET request to synchronise groups

inc/myco_objects.js

@@ -404,7 +404,7 @@ function SyncServer() {
     this.email=email;
     this.password=password;
     try {
-      jQuery.getJSON(
+      jQuery.post(
         this.url+'/sync',
         {
           'email':email,
@@ -421,7 +421,8 @@ function SyncServer() {
             }
           }
           onerror(data);
-        }
+        },
+        'json'
       ).fail(onerror);
     }
     catch(e) {