Merge pull request #3 from stitchfix/nil-dot-rewind-errors

Fallback to StringIO to prevent nil.rewind errors

lib/rspec_api_documentation/client_base.rb

@@ -44,7 +44,7 @@ def process(method, path, params = {}, headers ={})
     end
 
     def read_request_body
-      input = last_request.env["rack.input"]
+      input = last_request.env["rack.input"] || StringIO.new
       input.rewind
       input.read
     end