Use ENV to set database connection in rails

gistfile1.rb

#In an initializer 

def ENV.[]= key, value
  if key == 'RAILS_DATABASE_CONNECTION'
    ActiveRecord::Base.establish_connection (JSON.parse(value))
  end
  store(key, value)
end

ENV["RAILS_DATABASE_CONNECTION"] = %Q{{"database":"foo","adapter":"sqlite3"}} #...