Deploy a staging server from CI

See merge request !17

Fix ci

Closes #59 and #60

See merge request !16

Single step execution tests were unwittingly relying on test run order, because some tests would cause AwesomeClass to be loaded. Fixed by using a different class name for the validation failure tests.

# Conflicts:
#   Gemfile.lock

- Move bin/ci-test to script/ci-test
- Move bin/test to script/test
- Split bin/start test case out into bin/test

- Separate files for core, dev and testing
- Fix bin/ci-test
- Add bin/test for running tests locally
- Some small YAML tweaks

Use git URL for ink_step gem in Gemfile

See merge request INK/ink-api!12

Add postgres/ to .gitignore

See merge request INK/ink-api!10

Update Docker instructions

See merge request INK/ink-api!13

Use Docker volume for postgres data?

See merge request INK/ink-api!14

docker volume create --name=pgdata