Add the option for connection strings

[nicolas-graves]

Hi !
Thanks for these useful lines of code :)

As an improvement, I needed to go to the source code to connect to a distant database. Maybe it would be a great option to add the option for connection strings (https://www.postgresql.org/docs/10/libpq-connect.html) so that users can easily connect to different postgresql instances or distant instances.

Might upload a MR if this helps :)