title: Dangers of putting a gem into a gemfile is someone trying to install it doesn't support the gem?
body: <p>If I have some coworkers that have an old version of Mac OS X that doesn't support the gem I want to use (<a href="https://github.com/julienXX/terminal-notifier" rel="nofollow noreferrer"><code>terminal-notifier</code></a> specifically), are there dangers of putting this into the <code>Gemfile</code>:</p>
  
  <pre><code>gem 'terminal-notifier'
  </code></pre>
  
  <p>Is there some way to say that it requires OS X 10.8 or greater? What happens if someone on &lt; 10.8 tries to install terminal-notifier? I'm on the latest os so I can't exactly test this.</p>