Move sf-field to a external helper

Instead of inside the builder function.

Author: davidlgj

src/services/builder.js

@@ -11,6 +11,9 @@ angular.module('schemaForm').provider('sfBuilder', ['sfPathProvider', function(s
   };
 
   var builders = {
+    sfField: function(args) {
+      args.fieldFrag.firstChild.setAttribute('sf-field', args.path);
+    },
     ngModel: function(args) {
       if (!args.form.key) {
         return;
@@ -147,9 +150,6 @@ angular.module('schemaForm').provider('sfBuilder', ['sfPathProvider', function(s
             tmpl.appendChild(div.childNodes[0]);
           }
 
-
-          tmpl.firstChild.setAttribute('sf-field',path + '[' + index + ']');
-
           // Possible builder, often a noop
           var args = {
             fieldFrag: tmpl,