title: "Could not find a version that satisfies the requirement" error for Django2 app installation
body: <p>I'm newbie Python/Django programmer.</p>
  
  <p>I created an application based on Django 2.0 and packaged it according to <a href="https://docs.djangoproject.com/en/2.0/intro/reusable-apps/" rel="noreferrer">the official document</a>.
  Then I run the command:</p>
  
  <pre><code>$ pip install --user django-easybuggy-0.1.tar.gz
  </code></pre>
  
  <p>However, I get the error and cannot install. </p>
  
  <pre><code>Processing ./django-easybuggy-0.1.tar.gz
  Collecting certifi==2018.1.18 (from django-easybuggy==0.1)
    Could not find a version that satisfies the requirement certifi==2018.1.18 (from django-easybuggy==0.1) (from versions: )
  No matching distribution found for certifi==2018.1.18 (from django-easybuggy==0.1)
  </code></pre>
  
  <p>Does anyone know the reason why the error occurs and how to fix it?</p>
  
  <p>In addition, I created <code>requirements.txt</code> by the command:</p>
  
  <pre><code>$ pip freeze &gt; requirements.txt
  </code></pre>
  
  <p>Steps to reproduce:</p>
  
  <ol>
  <li><p>Download my application archive:</p>
  
  <pre><code>$ wget https://github.com/k-tamura/easybuggy4django/releases/download/0.0.1/django-easybuggy-0.1.tar.gz
  </code></pre></li>
  <li><p>Run the command:</p>
  
  <pre><code>$ pip install --user django-easybuggy-0.1.tar.gz
  </code></pre></li>
  </ol>
  
  <p>Best regards,</p>