Create Postgres Adaptor

[Bastien Boutonnet]

Here's an interesting article which may help when setting this up.
https://docs.github.com/en/free-pro-team@latest/actions/guides/creating-postgresql-service-containers

[Bastien Boutonnet]

Starting work on this.

TODO:

• try and get a sense of what db opearations are needed so that I can fixate the requirements for the Profile object. I might be able to figure this out from the kind of requirements dbt puts on postgres setups. Right now it looks like this:

postgres_db:
    db_type: postgres
    user: sheetwok_user
    password: magical_password
    host: localhost
    database: sheetwork_test
    schema: sheetwork_test_schema
    guser: [e-mail]

[Bastien Boutonnet]

Implemented by #314