title: How to set DATABASE_URL environment variable for Postgres Mac terminal?
body: <p>I am using postgres on Mac. I have a database up and running. I want to use it with Flask (SQL Alchemy) but the <code>DATABASE_URL</code> environment variable didn't create itself (I think it's supposed to do that). Here is the code I tried running:</p>
  
  <pre><code>import os
  print(os.getenv("DATABASE_URL"))
  </code></pre>
  
  <p>And there's no output. How can I set the variable (if I need to set it up manually).</p>