app.py

import flask
import os

app = flask.Flask(__name__, template_folder="./templates/")

@app.route('/')
def index():
    print('Route: /')
    return flask.render_template('index.html')

if __name__ == '__main__':
    app.run(host='0.0.0.0',  port=int(os.environ.get('PORT', 7860)))