title: how to add a primary key to a table in rails
body: <p>Hi I have a table in my rails app that doesnt have any id column or primary key. thats because this table was brought into my rails app from a previous app and the table is prepopulated with data. I now realize that without a integer primary key, rails cannot display edit and show views in the browser. So i ned to add a id column to my database that is a primary key and that autoincrements.</p>
  
  <p>Based on my googling, I came across a few posts about creating primary keys for a table but nothing that was complete.</p>
  
  <p>So Im wondering if someone can give me a hand here. So far what I know is in order to change the table one must write a migration and then run it.  The command that needs to be run for adding a id column is as follows: </p>
  
  <pre><code>rails generate migration add_id_to_businesses id:primary_key
  </code></pre>
  
  <p>However after running this command no new column is added to my database. Im not sure how to  proceed.. How do I add a new column to my database?</p>
  
  <p>Would really appreciate a hand.....
  Thanks,</p>