title: Rails: may have been in progress in another thread when fork() was called
body: <p>After I upgrade to OS10.14, I got this error when I called <code>Httparty</code></p>
  <pre><code>    response = HTTParty.get('http://api.stackexchange.com/2.2/questions?site=stackoverflow')
  objc[4182]: +[__NSPlaceholderDictionary initialize] may have been in progress in another thread when fork() was called.
  objc[4182]: +[__NSPlaceholderDictionary initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.
  </code></pre>
  <p>I already tried
  <code>export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES</code> before I start rails console.</p>
  <p>But it didn't work.</p>