please add support for postgres sslmode ?

[xxdesmus]

I'm trying to use DigitalOcean's managed postgres platform, and they require sslmode = require which it seems the code currently does not support/assume.

I tried my own hacky solution, but that has not been successful. I barely know what I'm doing.

[scrapbird]

Hey @xxdesmus I'll take a look at adding this if I find some time, not sure when that'll be at the moment though. I'll accept any pull request sent through in the meantime.