Rails::Initializer should assure ERB is loaded before reading database.yml

I was trying to create an environment where only ActiveRecord was
loaded, but since ERB is loaded by ActionPack, when reading and
interpreting database.yml on initializer.rb, it raises an error.

To fix I just needed to add the line below to railties/lib/
initializer.rb, on the database_configuration method (around line
700):

require 'erb' unless defined?(ERB)

So we have:

def database_configuration
  require 'erb' unless defined?(ERB)
  YAML::load(ERB.new(IO.read(database_configuration_file)).result)
end

Ticket at:
http://rails.lighthouseapp.com/projects/8994/tickets/722-rails-initializer-should-assure-erb-is-loaded-before-reading-database-yml