* Updated docker.py to allow for custom PSQL env input
* Updated README.md with new PSQL env variables
* Updated with new variable names and adjusted inline logic
* Updated README.md to reflect new env variable names
* Updated database password fallback to prevent breaking existing deployments
* Updated with new env variables
* Further edits per PR discussion
* Removed unnecessary variables from example docker-compose file
The docker-compose example now runs out of the box, when the env variables are supplied. Migrations are
applied at startup and cachetable is created.
Closes#141