Please install the postgresql adapter: gem install activerecord-postgresql-adapter
(pg is not part of the bundle. Add it to Gemfile.)
So I followed the instructions here: How to handle Ruby on Rails error: "Please install the postgresql adapter: `gem install activerecord-postgresql-adapter'"
First of all, that doesn't fix my issue (causes other errors that I'd need to debug), but regardless, why should I have to install the PG interface for ruby exactly? I'm on mysql!
Edit: I've been told Heroku doesn't support MySQL. Was this a recent change? I was using mysql just about 3 months back for my Heroku site without any issues at all.