add index README.md

[fix] heroku deploy setting

[fix] conform to PEP8

[fix] wrong output for get a user

[feature] db relationship use back_populates

[fix] item's price in store is wrong type

[feature] use FLASK_ENV to assign config

Merge branch 'feature-Use-flask-restx' into dev

[feature] conversion store related operations

[feature] conversion item related operations

[feature] conversion user action

[init] dev local environment

[depoly] Adding Heroku required files and setting

[feature] add user Logout resource

[feature] add jwt Blacklist check