Generate a random 64-byte ASCII string (I typically just run import random; ''.join('%02x' % random.randrange(256) for i in xrange(32)) at the Python interpreter)
Put that string into main.py on the line app.secret_key = key = 'SECRET HERE'
(Optional) Change the database password in docker-compose.yml and model.py -- default is dbpassword. This is not exposed to the outside so it's largely irrelevant
Search for ssrftest.com and replace it with the IP/domain you're hosting this on