title: Rails 3 check if attribute changed
body: <p>Need to check if a block of attributes has changed before update in Rails 3.</p>
  
  <p>street1, street2, city, state, zipcode</p>
  
  <p>I know I could use something like</p>
  
  <pre><code>if @user.street1 != params[:user][:street1]
    then do something....
  end
  </code></pre>
  
  <p>But that piece of code will be REALLY long.  Is there a cleaner way?</p>