This PR contains two changes to the code template. First, it improves
the CI process by moving the database migration process into Heroku's
release process that defined in `Procfile`. By doing so, we can cut down
two jobs from the deployment process in the CI pipeline. See 
https://devcenter.heroku.com/articles/release-phase for more
information about release process during deployment process on
Heroku.

Second, this PR updates the English translation of README.md. Each
step in the "How to Use" section is described more verbose and there
is a new section "Next Actions" to give an idea what should be done
next after setting up the Django Web project.