Merge pull request #13 from drewish/make-sprokets-optional

Don't assume sprockets is loaded

lib/swagger_rails/engine.rb

@@ -7,7 +7,9 @@ module SwaggerRails
     initializer 'swagger_rails.initialize' do |app|
       middleware.use SwaggerJson, SwaggerRails.config
 
+      if app.config.respond_to?(:assets)
         app.config.assets.precompile += [ 'swagger-ui/*' ]
       end
     end
+  end
 end