Weak support for 'ForwardRef' with python 3.6.8 #8

Hi @tiangolo ,

Thanks a lot for your amazing contributions. fastapi 🎈 . dockerswarmrocks 🌟 , and all projects generators 🚀

I just hit an issue when creating my first one-to-many relationship, as described in fastapi/fastapi#153.

One straightforward solution is to move up the python version from 3.6 to 3.7 in the Dockerfile(s).

So you have any particular advices to do this ? or shall I just create a PR with the 3 corrections ?

Emmanuel
-- cortexia.ch