Flask Rookie Guide
Flask is a famous microframework in Python, extensible for plugins. Besides, it only maintains one core. Comparing with Django, Django is more like a overall computer of a big brand, leaving you nothing to be worried about and offering you whatever you need. And for Flask, it's more like an assemble computer, or a well designed CPU, more precisely. So it's quite flexible for you to choose the fittings(plugins) you need.