Ensure Ruby server doesn't have duplicate id fields in json

Alternative approach to reactjs#115

Author: zpao

server.rb

@@ -25,7 +25,7 @@
     # Assume it's well formed
     comment = { id: (Time.now.to_f * 1000).to_i }
     req.query.each do |key, value|
-      comment[key] = value.force_encoding('UTF-8')
+      comment[key] = value.force_encoding('UTF-8') unless key == 'id'
     end
     comments << comment
     File.write(