Revert "Revert "Merge branch 'master' of https://github.com/discourse/discourse""

This reverts commit 20780a1eee.

* SECURITY: re-adds accidentally reverted commit:
  03d26cd6: ensure embed_url contains valid http(s) uri
* when the merge commit e62a85cf was reverted, git chose the 2660c2e2 parent to land on
  instead of the 03d26cd6 parent (which contains security fixes)

app/models/application_request.rb

@@ -16,15 +16,16 @@ class ApplicationRequest < ActiveRecord::Base
   include CachedCounting
 
   def self.disable
-    @enabled = false
+    @disabled = true
   end
 
   def self.enable
-    @enabled = true
+    @disabled = false
   end
 
   def self.increment!(type, opts = nil)
-    perform_increment!(redis_key(type), opts) if @enabled
+    return if @disabled
+    perform_increment!(redis_key(type), opts)
   end
 
   def self.write_cache!(date = nil)