title: Nuget Pack not including new files
body: <p>I've added new models and helpers to my project, but when I run <code>nuget pack</code> and install the package in my project I don't see the new items in the Assembly Explorer nor can I use them.  Am I missing something during the build that wouldn't include new files added to the package?</p>
  
  <p>I'm using visual studio 2017 and the nuget cli</p>