Try it without dotenv in prod env

to see if heroku can pull the secret key out of ENV if it's not there.
nup - still can't handle the ENV
Add capacity for venues

It's important to know how many people can fit in.
Revert "nup - still can't handle the ENV"

I've switched on heroku's compile-time environment variables, so hopefully
this will now work.

This reverts commit 077dceffd9e723fe15eadce698d2a2087264e729.
simple and advanced searches

still pretty simple advanced search,
but you can now search for venues based on price capacity and a keyword.

these searches are saved - and if you're logged in, they are saved as yours.
(later I'll add a list of them so you can come back to them)
Add saved searches

also add better test-coverage for searches, saved or otherwise.