title: Heroku migration: PG::Error: ERROR: relation "roles" does not exist
body: <p>When I run the command <code>heroku run rake db:migrate</code> for deploy my app to Heroku, I get this error:</p>
  
  <pre><code>PG::Error: ERROR:  relation "roles" does not exist
  :             SELECT a.attname, format_type(a.atttypid, a.atttypmod), d.adsrc, a.attnotnull
                FROM pg_attribute a LEFT JOIN pg_attrdef d
                  ON a.attrelid = d.adrelid AND a.attnum = d.adnum
               WHERE a.attrelid = '"roles"'::regclass
                 AND a.attnum &gt; 0 AND NOT a.attisdropped
               ORDER BY a.attnum
  
  Tasks: TOP =&gt; db:reset =&gt; environment
  (See full trace by running task with --trace)
  </code></pre>
  
  <p>Also I have tried <code>heroku run rake db:reset</code> or <code>heroku restart</code>, but didn't help me.</p>
  
  <p>The RoR &amp; PostgreSQL version I used in the app is </p>
  
  <pre><code>gem 'rails', '3.2.1'
  gem 'pg', '~&gt; 0.13.2'
  </code></pre>
  
  <p>On localhost is working everything well, but because of this error I can migrate my database to Heroku.</p>
  
  <p>Could anyone give me please some advice, how to solve this problem?</p>
  
  <p>Thank you so much</p>