Remove references to the Stripe gem

Rather than figure out how to upgrade the Stripe gem to be compatible with future Rails, I'd rather just delete the references, since it's currently unused.

I'm not so bold as to go in and fully trash all our donation code; I just want to ensure we're not sending people down broken codepaths, and that if they reach them, the error messages are clear enough.

Gemfile

@@ -69,8 +69,6 @@ gem 'rack-attack', '~> 2.2.0'
 
 gem 'react-rails', '~> 0.8.0.0'
 
-gem 'stripe', :git => 'https://github.com/stripe/stripe-ruby'
-
 gem "letter_opener", :group => :development
 
 gem 'sass-rails',    "~> 3.2.6"

Gemfile.lock

@@ -35,14 +35,6 @@ GIT
   specs:
     RocketAMF (1.0.0)
 
-GIT
-  remote: https://github.com/stripe/stripe-ruby
-  revision: 8c6dc1a838db0d39d9083431f6a4a8287f25d814
-  specs:
-    stripe (1.23.0)
-      json (~> 1.8.1)
-      rest-client (~> 1.4)
-
 GEM
   remote: http://rubygems.org/
   specs:
@@ -335,7 +327,6 @@ DEPENDENCIES
   rvm-capistrano (~> 1.5.6)
   sanitize (~> 2.0.3)
   sass-rails (~> 3.2.6)
-  stripe!
   swf_converter (~> 0.0.3)
   uglifier (>= 1.0.3)
   whenever (~> 0.7.3)

app/views/campaigns/show.html.haml

@@ -6,6 +6,7 @@
     toward #{@current_campaign.purpose}.
     Thanks so much!
 
+-# TODO: Reinstall Stripe before showing the checkout form
   = form_tag donations_path, method: 'POST', id: 'donation-form',
       'data-checkout-image' => image_path('default_preview.png'),
       'data-checkout-publishable-key' => Rails.configuration.stripe[:publishable_key],

config/initializers/stripe.rb

@@ -1,6 +1,27 @@
+# TODO: Upgrade Stripe to be usable again, or remove references altogether
+
 Rails.configuration.stripe = {
-  :publishable_key => ENV.fetch('STRIPE_PUBLISHABLE_KEY'),
+  :publishable_key => "REMOVED:STRIPE_PUBLISHABLE_KEY",
-  :secret_key      => ENV.fetch('STRIPE_SECRET_KEY')
+  :secret_key      => "REMOVED:STRIPE_SECRET_KEY"
 }
 
-Stripe.api_key = Rails.configuration.stripe[:secret_key]
+# Stripe.api_key = Rails.configuration.stripe[:secret_key]
+
+# Some stub methods for our Stripe calls, to give clearer error messages (but
+# those code paths shouldn't be accessible by normal users rn anyway).
+module Stripe
+  class Customer
+    def self.create(*args)
+      raise NotImplementedError, "TODO: Reinstall Stripe"
+    end
+  end
+
+  class Card
+    def self.create(*args)
+      raise NotImplementedError, "TODO: Reinstall Stripe"
+    end
+  end
+
+  class CardError < Exception
+  end
+end