increment

# File activesupport/lib/active_support/cache/mem_cache_store.rb, line 59
      def increment(key, amount = 1)       
        log("incrementing", key, amount)
        
        response = @data.incr(key, amount)  
        response == Response::NOT_FOUND ? nil : response
      rescue MemCache::MemCacheError 
        nil
      end