title: How to use VisualStudio build configuration to define DEBUG for dotnet Core project?
body: <p>As far as I know, <code>Debug.Assert</code> will not work without <code>"define": [ "DEBUG" ]</code> in project.json. I want to have it on dev machine and strip out on build server. 
  Should I just modify project.json as txt file after checkout on build server, or there is more elegant way?</p>
  
  <p>PS. I know about "project.json in 2017".</p>