SQLite support

[igalarzab]

Hi,

First of all thanks for developing the project, it's great! :)

I run it with a very simple setup and I would like to use a sqlite DB instead of requiring a full postgresql instance.

Would you be interested in a PR with this change? I could give it a try.

Thanks!

[zhjch05]

Yes, as long as it support both SQLite and postgres depending on a env var configuration. Would appreciate your contribution on that PR.