Added documentation for disable_offline_queue option

Signed-off-by: DTrejo <david.trejo@voxer.com>

README.md

@@ -197,6 +197,11 @@ be loading the database from disk.  While loading, the server not respond to any
 `node_redis` has a "ready check" which sends the `INFO` command to the server.  The response from the `INFO` command
 indicates whether the server is ready for more commands.  When ready, `node_redis` emits a `ready` event.
 Setting `no_ready_check` to `true` will inhibit this check.
+* `enable_offline_queue`: defaults to `true`. By default, if there is no active
+connection to the redis server, commands are added to a queue and are executed
+once the connection has been established. Setting `enable_offline_queue` to
+`false` will disable this feature and the callback will be execute immediately
+with an error, or an error will be thrown if no callback is specified.
 
 ```js
     var redis = require("redis"),