replacing json.dumps with flask jsonify helper wrapper

[daghan]

Hi there,

We have a free program analysis tool for Python based web projects, called Bento. While we were scanning GitHub projects for issues, your project triggered a warning for using json.dumps() instead of flask jsonify(). My sense is that you chose to use json.dumps() because jsonify() didn't support lists. That issue is fixed now (https://flask.palletsprojects.com/en/1.1.x/changelog/#version-0-11).

You may also want to look into updating the async function in app/decorators.py, since it is a Python keyword starting from 3.7. But I didn't touch it to keep this PR simple.

Bento also flagged the async function in app/decorators.py, since it is a Python keyword starting from 3.7. But I didn't touch it to keep this PR simple. If you are interested, feel free download and give Bento a try (https://bento.dev).