add user to README.md

Author: leibale

README.md

@@ -182,6 +182,7 @@ using unix sockets if possible to increase throughput.
 | enable_offline_queue       | 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 executed immediately with an error, or an error will be emitted if no callback is specified.                                                                                                                                                                                                                          |
 | retry_unfulfilled_commands | false     | If set to `true`, all commands that were unfulfilled while the connection is lost will be retried after the connection has been reestablished. Use this with caution if you use state altering commands (e.g. `incr`). This is especially useful if you use blocking commands.                                                                                                                                                                                                                                                                                                |
 | password                   | null      | If set, client will run Redis auth command on connect. Alias `auth_pass` **Note** Node Redis < 2.5 must use `auth_pass`                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
+| user                       | null      | The ACL user (only valid when `password` is set)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
 | db                         | null      | If set, client will run Redis `select` command on connect.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
 | family                     | IPv4      | You can force using IPv6 if you set the family to 'IPv6'. See Node.js [net](https://nodejs.org/api/net.html) or [dns](https://nodejs.org/api/dns.html) modules on how to use the family type.                                                                                                                                                                                                                                                                                                                                                                                 |
 | disable_resubscribing      | false     | If set to `true`, a client won't resubscribe after disconnecting.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |