Add instructions to start psql

[ghost]

Issue by Scott Hood added to SQL channel:

Apologies if this is the wrong place to post this (I'm new, hi :wave:) but I just had a question about the prep work for this module.For Windows users it recommends using WSL and following the Ubuntu steps. Then once you get to this step to create your user and database, the command fails with a could not connect to server error.To fix this, I had to manually start the service myself with sudo service postgresql start and then everything worked fine.Just wondering if this is the right way to handle this and this is just missing from the documentation or if there is something I'm missing.