"pg is not part of the bundle. Add it to Gemfile" when not using Postgres

Question

Here's my problem:

• I create a new project: rails new myapp.
  Rails applications are by default configured to use a SQLite3 database.

• I execute bundle exec rake db:create. It works and the SQLite3 database is created.

• I try to create a new model (or anything else related to the database), and get the following error:

  /home/dinduks/.rvm/gems/ruby-1.9.3-p194/gems/bundler-1.1.3/lib/bundler/rubygems_integration.rb:147:in block in replace_gem': Please install the postgresql adapter:gem install activerecord-postgresql-adapter` (pg is not part of the bundle. Add it to Gemfile.) (LoadError)

• When I add a controller and an action, and try to visit it, I get this error:

  ActiveRecord::ConnectionNotEstablished (ActiveRecord::ConnectionNotEstablished)

  The complete stack trace can be found here: https://gist.github.com/2717365
  The WEBrick server starts obviously without complaining.

I reinstalled Rails, reinstalled Ruby, used another Ruby version, reinstalled RVM... And keep getting the same error.

There is nothing related to PostgreSQL, postgres, pg or pql in my code. Not a single word.

I don't want to do what the exception suggests. I want to understand why I have this error and fix it.

So: Why is Rails asking me to install some Postgres stuff while I don't use Postgres?

Thanks!

Answer 1

The problem was the DATABASE_URL environment variable.
When ActiveRecord finds $DATABASE_URL, it automatically uses its information, and ignores config/database.yml.

Thanks to NARKOZ for pointing this out.

(By the way, I had this environment variable set before I discover foreman, which is a great tool to manage environment variables)