docs: Include instructions on mysql manual setup

- how to use env vars
- how to setup db
- more words on virtualenv

Signed-off-by: David Haynes <dhaynes3@gmu.edu>
3 jobs for 32-mysql-move in 47 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Test
passed whats-open-py2.7 #2366

00:00:39

passed whats-open-py3.5 #2367

00:00:42

passed whats-open-py3.6 #2368

00:00:46