How do you set up a second database connection without the use of any yaml files?

I have an app running on Heroku and I want to set up a connection to a second database (from another app running on Heroku). All solutions I have seen for multiple DBs involve the database.yml file, but Heroku does not do things this way, they instructed me to use DATABASE_URL from one app in the other.

I think I need to do something like:

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DatabaseName::Base.establish_connection(DATABASE_URL)

and then I can use

establish_connection :DatabaseName

in the appropriate models. Where do I put

DatabaseName::Base.establish_connection(DATABASE_URL)

to have it available to all models? environment.rb? And what is the correct syntax for it?

---

Assuming you have two dbs DBOne and DBTwo which you want to connect (please fill up the data accordingly). Hope that helps.

   class DBOne < ActiveRecord::Base
    self.abstract_class = true
    establish_connection(
      :adapter  => "mysql",
      :host     => "hostname",
      :username => "myuser",
      :password => "mypass",
      :database => "database_one"
    )
    end

    class ModelInDbOne <DBOne
    end

    class DBTwo < ActiveRecord::Base
    self.abstract_class = true
    establish_connection(
      :adapter  => "mysql",
      :host     => "hostname",
      :username => "myuser",
      :password => "mypass",
      :database => "database_two"
    )
    end 

    class ModelInDbTwo < DBTwo
    end