memoryStore.set() 增加 maxAge参数

lib/stores/memory.js

@@ -18,8 +18,13 @@ var memoryStore = function(args) {
     self.set = function(key, value, options, cb) {
         if (typeof options === 'function') {
             cb = options;
+            options = {};
         }
-        lruCache.set(key, value);
+        options = options || {};
+
+        var maxAge = (options.ttl || options.ttl === 0) ? options.ttl : lruOpts.maxAge;
+
+        lruCache.set(key, value, maxAge);
         if (cb) {
             process.nextTick(cb);
         }