When running 'rake test:prepare' from SSH terminal on the test environment that has a Heroku PostgreSQL database, you will be presented with a Permission Denied error. The following is a simple workaround for that issue.

Heroku Postgres test:prepare Workaround

rake db:migrate VERSION=0 RAILS_ENV=test; rake db:migrate RAILS_ENV=test;

# If you do not have RVM v1.11 installed, you may have to use 'bundle exec' infront of your rake commands, like so:
# bundle exec rake db:migrate VERSION=0 RAILS_ENV=test; bundle exec rake db:migrate RAILS_ENV=test;