Unable to query data from MongoAlchemy with Flask app

Question

So I'm trying to learn Flask and MongoDB using MongoAlchemy and I'm running into an issue when trying to query my app for data, I'm not sure what I'm doing wrong. I've searched through the MongoAlchemy documentation and followed a few StackOverflow posts to no real avail. Here's my code:

from flask import Flask, jsonify, request
from flask_mongoalchemy import MongoAlchemy

app = Flask(__name__)
app.config['MONGOALCHEMY_DATABASE'] = 'user'
app.config['MONGOALCHEMY_SERVER_AUTH'] = False
db = MongoAlchemy(app)

class User(db.Document):
    user_name = db.StringField()
    password = db.StringField()
    first_name = db.StringField()
    last_name = db.StringField()
    phone_number = db.StringField()

def init_app():
    app = Flask(__name__)
    db.init_app(app)
    return app

user_1 = User(user_name = "user1", 
    password = "password", 
    first_name = "John", 
    last_name = "Doe",
    phone_number = "123-456-7890")

user_1.save()

@app.route('/', methods=['GET', 'POST'])
def index():
    return "Hello, world!"

@app.route('/user/<user_name>', methods=['GET', 'POST'])
def findUser(user_name=None):
    uName = request.args.get('user_name', user_name)
    user = User.query.filter({User.user_name:uName}).first()
    return jsonify(user)


##=====================================================================

if __name__ == '__main__':
    app.run(debug=True)

When I go to localhost:5000/user/user1 it returns null, I'm not sure what I'm doing wrong? Thanks in advance!

Referenced Posts: MongoAlchemy query embedded documents

Flask Value error view function did not return a response

http://www.mongoalchemy.org/api/schema/document.html