Setting IHostingEnvironment.IsDevelopment as True in an ASP.NET 5 Application

I am now in Frankfurt, sipping my coffee in a Starbucks shop and enjoying its rubbish internet connection (as usual). I have just thrown away 10 minutes from my life by trying to figure out why my ASP.NET 5 application wasn't showing the error page. So, I wanted to write this quick and dirty blog post for people who will potentially have the same problem :)

Here is the piece of code I have inside the Configure method of my Startup class:

public void Configure(IApplicationBuilder app, IHostin...