Content Type Headers

1. Assert that a POST request to "/api/level18" returns a 200 status code.
2. Assert that a POST request to "/api/level18" with a header of "Content-Type" with a value of "text/plain", and body of "Just plain ol talkin" returns the response:

   Understood.

3. Assert that a POST request to "/api/level18" with header of "Content-Type" with a value of "application/json", and body of:

   {
     "how": "about this?"
   }

   returns the response:

   {
     "Yup": "got it"
   }

Nailed It!