model

class OrderRecord < ActiveRecord::Base
  establish_connection :db_name
end

database.yml

db_name:
  adapter: postgresql
  encoding: unicode
  database: xxx_development
  pool: 5
  # port: 54321
  # host: localhost
  host: 'xxx.xxx.xxx'
  username: xxxx
  password: none

#1 楼 @fresh_fish thx!