remove custom json serializer

api/__init__.py

@@ -1,13 +1,9 @@
 from flask import Flask, jsonify
 from flask_sqlalchemy import SQLAlchemy
-from api.helpers import JSONEncoder
 
 app = Flask(__name__)
 app.config.from_object('config')
 
-# enable this when json encoding works
-# app.json_encoder = JSONEncoder
-
 def on_404(e):
   return jsonify(dict(error='Not found')), 404