title: Force pipenv to create a new virtualenv
body: <p>I installed pip by downloading <code>virtualenv</code>, and creating a bootstrap virtualenv, as described in <a href="https://stackoverflow.com/a/5598559/4794">this answer</a>.</p>
  
  <p>Now I want to try out <code>pipenv</code>, so I used my bootstrap virtualenv to create a new virtualenv and then ran <code>pip install pipenv</code>. Now I can use <code>pipenv</code>, but it sees that it's already running in a virtualenv and doesn't create a new one.</p>
  
  <p>How can I get <code>pipenv</code> to create a new virtualenv so I can have separate virtualenvs for each project? I tried <code>pipenv install -h</code>, but none of the options look promising.</p>