Connecting to an external DB

I am trying to connect to an external database from my Rails
application. In my datanase.yml file, I have the following:

  adapter: mysql2
  database: external_src
  username: external_src
  password: mypassword

The database is going to called to retrieve data for display in one of
the pages. I do have a pages controller, but I do not have a pages
model, so I created a pages mode, pages.rb and added the following to

class Blog < ActiveRecord::Base
  set_table_name :posts

Now, in my pages controller, how do I retrieve data? Let's say I have a
table in that database called pots and I would like to retrieve the post
with the id 2? I tried: Blog.find(2), but I am getting the following
error message: uninitialized constant PagesController::Blog

Any ideas?