title: No module named 'psycopg2' Error in Scrapy
body: <p>When I use </p>
  
  <pre><code>import psycopg2
  </code></pre>
  
  <p>in <strong>Scrapy</strong> <em>pipeline.py</em> or <em>spider.py</em> I get the following error</p>
  
  <pre><code>ModuleNotFoundError: No module named 'psycopg2'
  </code></pre>
  
  <p>I know that the error is not valid, because I am running Django server with postgresql, using same venv which contains psycopg2. And also I can connect to db in a test file and enquiry as well. In addition I can run <em>import psycopg2</em> in Scrapy shell with no issue. So it has puzzled me that I might be missing something,
  I appreciate if someone can help me,</p>