Raise if NODE_ENV is not set

Author: gauravtiwari

lib/webpacker/env.rb

@@ -40,7 +40,7 @@ def available_environments
     def node_env
       ENV.fetch("NODE_ENV")
     rescue KeyError
-      logger.info "Using webpacker requires that you set NODE_ENV environment variables. " \
+      raise "Using webpacker requires that you set NODE_ENV environment variables. " \
             "Valid values are #{available_environments.join(', ')}"
     end
 end