Add flask-cors to dockerfile

Author: Michael Phelps

Dockerfile

@@ -120,6 +120,6 @@ ENV APP_HOME /app
 WORKDIR $APP_HOME
 COPY . $APP_HOME
 
-RUN pip install Flask gunicorn .
+RUN pip install Flask flask-cors gunicorn .
 
 CMD exec gunicorn --bind :$PORT --workers 1 --threads 8 --timeout 0 --chdir $APP_HOME/pytago pytago.web:app