Replace comma with a regexp that matches commas, newlines or comma+newlines

Database models can now be declared (in the config file) with newlines as well as commas. This helps keeping the config file readable when there's a lot of models to add.

I've run the tests and the only one that doesn't pass is a tests that didn't pass on my machine even when I had just cloned the repo so I think it's something due to my local configs.