PERF: Fix memory leak

We used to leak some memory every time you cook a post

see: https://github.com/cowboyd/therubyracer/pull/336

lib/freedom_patches/fix_rubyracer_memory_leak.rb

@@ -0,0 +1,33 @@
+## TODO: DELETE ME WHEN https://github.com/cowboyd/therubyracer/pull/336
+# is upstreamed and released
+#
+module V8
+  module Weak
+      class WeakValueMap
+        def initialize
+          @values = {}
+        end
+
+        def [](key)
+          if ref = @values[key]
+            ref.object
+          end
+        end
+
+        def []=(key, value)
+          ref = V8::Weak::Ref.new(value)
+          ObjectSpace.define_finalizer(value, self.class.ensure_cleanup(@values, key, ref))
+
+          @values[key] = ref
+        end
+
+        private
+
+        def self.ensure_cleanup(values,key,ref)
+          proc {
+            values.delete(key) if values[key] == ref
+          }
+        end
+      end
+  end
+end