Boilerplate Code
#main.py
from flask import Flask
from controllers.index import Index

app = Flask(__name__)

Index.register(app, route_base='/')

if __name__ == '__main__':
  app.run(debug=True)
#controllers/index.py
from flask import render_template
from flask_classful import FlaskView, route

class Index(FlaskView):
    def __init__(self):
        pass

    @route('/')
    def index(self):
        return render_template('index.html', data={'blogTitle':'រៀន​ពីចំងាយ'})

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8"/>
    <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
    <title>{{data['blogTitle']}}</title>
    <script src="/static/scripts/jQuery.js"></script>
    <script src='/static/scripts/main.js'></script>
    <link href="/static/styles/index.css" rel="stylesheet">
    <link href="/static/fonts/setup.css" rel='stylesheet'>
    <link href="/static/images/site_logo.png" rel="icon">
  </head>
  <body>
    ស្វាគមន៍​មក​កាន់​កម្មវិធី​កេហទំព័រ «រៀន​ពី​ចំងាយ»
  </body>
</html>

GitHub: "https://github.com/Sokhavuth/E-Learning
Heroku: https://khmerweb-elearning.herokuapp.com/