Merge pull request reidmorrison#93 from dck/master

Check the specific method existance for Spring after_fork

Author: reidmorrison

lib/rails_semantic_logger/engine.rb

@@ -189,7 +189,7 @@ class Engine < ::Rails::Engine
       Resque.after_fork { |_job| ::SemanticLogger.reopen } if defined?(Resque)
 
       # Re-open appenders after Spring has forked a process
-      Spring.after_fork { |_job| ::SemanticLogger.reopen } if defined?(Spring)
+      Spring.after_fork { |_job| ::SemanticLogger.reopen } if defined?(Spring.after_fork)
     end
   end
 end