* Remove duplicate Procfile added in 6b48ec6. The new duplicate was
not being used in the script. The older templates/Procfile was used.
* Remove duplicate `copy_file 'Procfile'` command. Keep new version so
there are fewer commands in non-intention-revealing method,
* Remove output instructing user to copy sample.env to .env. This output
is likely to get lost in the rest of the ouput. We also want to
automate that step in #120.
* Remove unnecessary comments: 1) No need to instruct user to copy file
because they should use script/setup. 2) Do not need to add .env to
.gitignore because Suspenders already ignores it. 3) Do not instruct
all developers to add Heroku config variables. That is a process
outside the scope of this file, better documented in
* Link to official documentation in sample.env.
* Remove HOSTNAME from sample.env. Developers should be able to override
the port from the command line.