docs/server.rb in preval-0.4.0 vs docs/server.rb in preval-0.4.1

@@ -9,9 +9,9 @@
 get '/' do
   send_file(File.expand_path('index.html', __dir__))
 end
 
 post '/' do
-  Preval.process(request.body.read).tap do |response|
+  Preval.process(request.body.read || '').tap do |response|
     halt 422 unless response
   end
 end