title: Unable to deploy fbprophet in heroku
body: <p>I am unable to deploy fbprophet time series model into heroku. Locally, it works well.</p>
  <p>The requirements.txt file contains as follows.</p>
  <pre><code>numpy
  pandas
  matplotlib
  pystan==2.19.1.1
  streamlit
  plotly
  fbprophet
  </code></pre>
  <p>Tried:
  Kept default pystan without giving the version. Did not work. Error in CLI showing &quot;Pystan loading&quot;.</p>
  <p>Error:</p>
  <pre><code>Failed to build pystan fbprophet
  Running setup.py install for pystan: started
  </code></pre>
  <p>No response after this.</p>