Sessions store in DB with with pg-connect-simple

DB table has to created manually, I added a note to the README file.
lots of re-ordering going on here.

I'm gonna guess that you did `npm install --save-dev` for a dependency that you added?

the dependencies were grouped a particular way before. I'm open to re-ordering them if that's what we want to do, but just take it as an FYI. also the commits should be atomic (e.g. for this changeset you could have one commit that updates the README, another commit that adds the dependency/dependencies that you need for the feature, a second commit that adds the new functionality that this pull request introduces, and then a third that re-orders the other dependencies, assuming that's what you wanted to do).

I'm a big advocate of `git add -p` to slice and dice (and review) a changeset before I decide what piece(s) of it should go into the commit.