title: Can't release pushed docker image in heroku
body: <p>I am pretty new to Heroku. </p>
  
  <h2>Issue Description</h2>
  
  <p>After successfully pushing a docker image to Heroku Container Registry using JIB I am struggling to release it.</p>
  
  <h2>What I did:</h2>
  
  <p>Pushed docker image using JIB:</p>
  
  <pre><code>[INFO] Built and pushed image as hamzablm/timesheet
  [INFO] Executing tasks:
  [INFO] [===========================   ] 88.9% complete
  [INFO] &gt; launching layer pushers
  [INFO] 
  [INFO] ------------------------------------------------------------------------
  [INFO] BUILD SUCCESS
  [INFO] ------------------------------------------------------------------------
  [INFO] Total time:  51.106 s
  [INFO] Finished at: 2020-04-20T11:16:20Z
  [INFO] ------------------------------------------------------------------------
  </code></pre>
  
  <p>By now the image should be in the registry.
  But when I want to release it:
  <code>heroku container:release hamzablm/timesheet</code> It fails:</p>
  
  <pre><code> ›   Error: Missing required flag:
   ›     -a, --app APP  app to run command against
   ›   See more help with --help
  </code></pre>
  
  <p>I'm probably missing something simple here, but any help would be appreciated.</p>