Configure CORS headers for submission endpoint

Gemfile

@@ -22,6 +22,7 @@ gem 'jbuilder'
 gem 'bootsnap', '>= 1.4.2', require: false
 
 gem 'google-api-client'
+gem 'rack-cors'
 
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console

Gemfile.lock

@@ -121,6 +121,8 @@ GEM
     puma (4.3.3)
       nio4r (~> 2.0)
     rack (2.2.2)
+    rack-cors (1.1.1)
+      rack (>= 2.0.0)
     rack-proxy (0.6.5)
       rack
     rack-test (1.1.0)
@@ -217,6 +219,7 @@ DEPENDENCIES
   listen
   pg
   puma
+  rack-cors
   rails
   sass-rails
   spring

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