title: How to use Homebrew on a Multi-user MacOS Sierra Setup
body: <p>I have a Mac that is shared between two engineers. Both have separate user accounts. Both need to run <code>brew update</code> and <code>brew install...</code> occasionally.</p>
  
  <p>How do I set this up without getting errors like:
  <code>/usr/local must be writable!</code>?</p>
  
  <p>Yeah, I could have <code>UserA</code> take over the permissions of <code>/usr/local</code> every time he wants to use brew (and same with <code>UserB</code>), but that seems like a lot of unnecessary trouble.</p>