Cannot run connector in Docker without specifying DATABASE_SCHEMA env variable

[lubomirw]

Describe the bug
When running service in Docker and not specifying env variable DATABASE_SCHEMA relying on default value, migration is not applied because it is missing schema, not using default value.

To Reproduce
Steps to reproduce the behavior:

1. Run service in Docker without specifying DATABASE_SCHEMA env variable
2. Look to logs

Expected behavior
Service should use default value for env variable as specified in README

Desktop (please complete the following information):

• OS: Docker container
• Browser: N/A
• Version: 1.1.2