PG::ConnectionBad: could not connect to server

[tomclose]

I'm trying to get pliny to run with the boxen-installed postgres instance on my macbook. I've updated the DATABASE_URL in .env and .env.test to match the BOXEN_POSTGRESQL_URL:

DATABASE_URL=postgres://127.0.0.1:15432/testapp-test

However, when I run bin/setup I get the following error at the rake db:setup stage:

rake aborted!
Sequel::DatabaseConnectionError: PG::ConnectionBad: could not connect to server: No such file or directory
    Is the server running locally and accepting
    connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

PG::ConnectionBad: could not connect to server: No such file or directory
    Is the server running locally and accepting
    connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

Tasks: TOP => db:setup => db:drop
(See full trace by running task with --trace)