diff --git a/lib/guard/jasmine/coverage.rb b/lib/guard/jasmine/coverage.rb
index 14df6b4..5300aa7 100644
--- a/lib/guard/jasmine/coverage.rb
+++ b/lib/guard/jasmine/coverage.rb
@@ -60,7 +60,9 @@ def self.coverage_bin
   #
   class GuardJasmineCoverageEngine < ::Rails::Engine
     initializer 'guard-jasmine.initialize' do |app|
-      app.assets.register_postprocessor 'application/javascript', JasmineCoverage
+      app.config.assets.configure do |env|
+        env.register_postprocessor 'application/javascript', JasmineCoverage
+      end
     end
   end