刚学flask，往数据库添加数据好像添加不进去，前端获取到的都是一个空数组，请问应该怎么找出原因？

Question

from flask import Flask, session
from flask import render_template
from flask_script import Manager
from flask import url_for
from flask import request, jsonify, json

from flask_cors import CORS

from flask_sqlalchemy import SQLAlchemy
import os

from flask_marshmallow import Marshmallow

basedir = os.path.abspath(os.path.dirname(__file__))


app = Flask(__name__)

cors = CORS(app, resources={r"/*": {"origins": "*"}})
app.config['SECRET_KEY'] = 'a string'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + \
                                        os.path.join(basedir, 'data.sqlite')

# 自动提交
app.config['SQLALCHEMY_COMMIT_TEARDOWN'] = True

app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

manager = Manager(app)
db = SQLAlchemy(app)
ma = Marshmallow(app)


class Article(db.Model):
    """docstring for Article"""
    __tablename__ = 'articles'
    id = db.Column(db.Integer, primary_key = True)
    title = db.Column(db.String(64))
    content = db.Column(db.Text)

class ArticleSchema(ma.ModelSchema):
    class Meta:
        medel = Article

@app.route('/')
def index():
    articles = Article.query.all()
    articles_schema = ArticleSchema()
    output = articles_schema.dump(articles).data
    return jsonify({'articles': output})


@app.route('/create', methods=['POST'])
def create():
    title = request.form['title']
    content = request.form['content']
    article = Article(title=title, content=content)
    db.session.add(article)
    session['known'] = False
    
    return content


if __name__ == '__main__':
    manager.run()