cache digests need an initializer to work with haml

rails/cache_digests#46

Author: azul

config/initializers/haml.rb

@@ -9,3 +9,8 @@
   Haml.init_rails(binding)
 end
 
+# enable cache_digests for haml templates...
+# https://github.com/rails/cache_digests/pull/46
+# UPGRADE - this can go away once we use rails4 with haml_rails v5
+CacheDigests::DependencyTracker.register_tracker :haml, CacheDigests::DependencyTracker::ERBTracker
+