Add Action Cable asset building as release step

tasks/release.rb

@@ -48,6 +48,7 @@
     task gem => %w(update_versions pkg) do
       cmd = ""
       cmd << "cd #{framework} && " unless framework == "rails"
+      cmd << "bundle exec rake assets:compile && " if framework == "actioncable"
       cmd << "gem build #{gemspec} && mv #{framework}-#{version}.gem #{root}/pkg/"
       sh cmd
     end