v2.1.0 (Task queues with rq)

New Content

• Section 12 on using task queues with rq to send emails through Mailgun, #83, #85

Updated Content

• Remove before_first_request in Flask apps, since now the recommended approach is to just do any necessary setup inside create_app(), #77
• Remove db.create_all() from create_app() when using Flask-Migrate, since it is Flask-Migrate that creates the tables, #78
• Add information to the e-book on how to make sure tag and item have the same store id when linking them, #79
• Added missing required arguments in Flask-JWT-Extended callbacks, #81
• Added missing hostname in the command to run Flask using the Flask development server in Docker, #82
• Use FLASK_DEBUG instead of FLASK_ENV across entire ebook and all projects since FLASK_ENV is now deprecated, #84
• Remove password's unique=True in all user models, #86