Add travis config

[bndr]

I hope you don't mind I added Travis config for you. It works (https://travis-ci.org/bndr/flask-peewee)

Werkzeug supports only 3.3+ so I removed the 3.2 from testing.

3.3 Test fails because the wtf-peewee package in the pypi is old, but should pass without any problems once it's updated.