Add Stripe-based billing system

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Co-Authored-By: Jason Zimdars <jz@37signals.com>

saas/app/controllers/admin/stats_controller.rb

@@ -0,0 +1,20 @@
+class Admin::StatsController < AdminController
+  layout "public"
+
+  def show
+    @accounts_total = Account.count
+    @accounts_last_7_days = Account.where(created_at: 7.days.ago..).count
+    @accounts_last_24_hours = Account.where(created_at: 24.hours.ago..).count
+
+    @identities_total = Identity.count
+    @identities_last_7_days = Identity.where(created_at: 7.days.ago..).count
+    @identities_last_24_hours = Identity.where(created_at: 24.hours.ago..).count
+
+    @top_accounts = Account
+      .where("cards_count > 0")
+      .order(cards_count: :desc)
+      .limit(20)
+
+    @recent_accounts = Account.order(created_at: :desc).limit(10)
+  end
+end