title: Prevent select2 from flipping the dropdown upward
body: <p>As per title, is there a way to force select2 to always create a dropdown instead of a drop-up?</p>
  
  <p>There also appears to be some javascript that is either causing the flip when you scroll above the dropdown, adding a new CSS class "select2-drop-above", or both.</p>
  
  <p>EDIT: I should've specified that I'm pulling the library in via select2-rails. I'm hoping there is a way around this that doesn't involve pulling the whole select2 lib in myself and editing the select2.js file directly.</p>