For your "stack", I'd recommend Heroku for the backend, and PostgreSQL for the database because it's supported well by Heroku. The name of the game is that you shouldn't have to spend any time setting up servers, etc. Just test and deploy. There's a good Flask tutorial by Miguel Grinberg in book form and online which uses this stack.
Django's learning curve is a bit steeper, but there are more resources out there. Stay persistent (and use Python 3)!
- An HTML templating language for your views
- An Object Relationship Mapper ("ORM" - makes talking to databases consistent, and automatically populates your models with data from the database)
- User Authentication/Session Management
- An Admin GUI for managing your database models ("CRUD" Actions - Create, Read, Update, Delete)