flask-peewee can be installed very easily using pip.
pip install flask-peewee
If you do not have the dependencies installed already, pip will install them for you, but for reference they are:
If you want to run the very latest, feel free to pull down the repo from github and install by hand.
git clone https://github.com/coleifer/flask-peewee.git cd flask-peewee python setup.py install
You can run the tests using the test-runner:
python setup.py test