Add rack-rewrite to handle redirects

We are moving bulk edit to a different route and we want to be able to
handle redirects on this route. Handling this at the rack level before
the rails stack is the most performant way outside of rewrites on the
web server itself.

Gemfile

@@ -58,6 +58,7 @@ gem 'geocoder'
 gem 'gmaps4rails'
 gem 'spinjs-rails'
 gem 'rack-ssl', require: 'rack/ssl'
+gem 'rack-rewrite'
 gem 'custom_error_message', github: 'jeremydurham/custom-err-msg'
 gem 'angularjs-file-upload-rails', '~> 1.1.6'
 gem 'roadie-rails', '~> 1.0.3'

Gemfile.lock

@@ -543,6 +543,7 @@ GEM
       rack (>= 0.4)
     rack-livereload (0.3.16)
       rack
+    rack-rewrite (1.5.1)
     rack-ssl (1.3.4)
       rack
     rack-test (0.6.3)
@@ -775,6 +776,7 @@ DEPENDENCIES
   pry-byebug (>= 3.4.3)
   rabl
   rack-livereload
+  rack-rewrite
   rack-ssl
   rails (~> 3.2.22)
   rails-i18n (~> 3.0.0)

config/initializers/rack_rewrite.rb

@@ -0,0 +1,7 @@
+module Openfoodnetwork
+  class Application < Rails::Application
+    config.middleware.insert_before(Rack::Lock, Rack::Rewrite) do
+      r301   '/admin/products/bulk_edit',  '/admin/products' # TODO: Date added 15/06/2018
+    end
+  end
+end