title: Rename existing rails model and add namespace
body: <p>Original code looks like this:</p>
  
  <pre><code># app/models/sso_configuration.rb
  class SsoConfiguration &lt; ActiveRecord::Base
  end
  
  # db/schema.rb
  create_table "sso_configurations", force: true do |t|
    ...
  end
  </code></pre>
  
  <p>I have to rename the model and add namespace so that I'll have <code>Sso::SamlConfiguration</code>. I changed model and database table.</p>
  
  <pre><code># db/migrate20160225144615_rename_sso_configurations_to_sso_saml_configurations.rb
  class RenameSsoConfigurationsToSsoSamlConfigurations &lt; ActiveRecord::Migration
    def change
      rename_table :sso_configurations, :sso_saml_configurations
    end
  end
  
  # db/schema.rb
  create_table "sso_saml_configurations", force: true do |t|
    ...
  end
  
  # app/models/sso/saml_configuration.rb
  module Sso
    class SamlConfiguration &lt; ActiveRecord::Base
    end
  end
  </code></pre>
  
  <p>When I open my rails console, the following happens.</p>
  
  <pre><code>&gt; Sso::SamlConfiguration
  =&gt; Sso::SamlConfiguration(Table doesn't exist)
  &gt; Sso::SamlConfiguration.new
  =&gt; PG::UndefinedTable: ERROR:  relation "saml_configurations" does not exist
  </code></pre>
  
  <p>My original thinking was that namespaced models should, by convention, have the snakecase name as the table name such that <code>Foo::Bar</code> should have a corresponding <code>foo_bars</code> table. Am I missing something with my setup?</p>