Connecting to multiple databases in rails in one application

The command you are looking for is establish_connection. You might
want to look at the rails rdoc. Search for "Connection to multiple
databases in different models" in http://api.rubyonrails.com/classes/ActiveRecord/Base.html.

eg:

class SomeModelDB1 < ActiveRecord::Base
  self.establish_connection("db1")
end

class SomeModelDB2 < ActiveRecord::Base
  self.establish_connection("db2")
end

database.yml
db1:
  adapter: mysql
  database: somedb
  username: user
  password: pass
  host: localhost
  socket: /tmp/mysql.sock
db2:
  adapter: mysql
  database: somedb2
  username: user
  password: pass
  host: remotehost