title: How do I ADD the pg gem in the production environment in Rails
body: <p>I am new to programming and using RAILS on Cloud9 IDE. I am having difficulty trying to push my app into Heroku. I get the error:...</p>
  
  <pre><code>Push rejected, no Cedar-supported app detected
  remote: HINT: This occurs when Heroku cannot detect the buildpack
  remote: 
  </code></pre>
  
  <p><strong>NOTE:</strong> The tutorial I am following tells me at Heroku setup section:</p>
  
  <blockquote>
    <p>Heroku uses the PostgreSQL database (pronounced “post-gres-cue-ell”,
    and often called “Postgres” for short), which means that we need to
    add the pg gem in the production environment to allow Rails to talk to
    Postgres:17</p>
  
  <pre><code> group :production do   
      gem 'pg', '0.17.1'   
      gem 'rails_12factor', '0.0.2’ 
   end
  </code></pre>
  </blockquote>
  
  <p>Question: How do I ADD the <code>pg</code> gem in the production environment (I suspect that the push rejected error is due to this)</p>