Configure CORS headers for submission endpoint

config/application.rb

@@ -15,5 +15,11 @@ module Tinyform
     # Application configuration can go into files in config/initializers
     # -- all .rb files in that directory are automatically loaded after loading
     # the framework and any gems in your application.
+    config.middleware.insert_before 0, Rack::Cors do
+      allow do
+        origins '*'
+        resource '/s/*', headers: :any, methods: [:post, :put, :options]
+      end
+    end
   end
 end