update readme for --tasks

README.md

@@ -30,6 +30,8 @@ Commands:
     rollback service
 ```
 
+For more options for sub-commands, See `ecspresso sub-command --help`.
+
 ### Configuration file
 
 YAML format.
@@ -73,6 +75,16 @@ Events:
 2017/11/09 23:23:29 myService/default Service is stable now. Completed!
 ```
 
+## Scale out/in
+
+To change desired count of the service, specify `--tasks` option.
+
+If `--skip-task-definition` is set, task definition will not be registered.
+
+```console
+$ ecspresso deploy --config config.yaml --tasks 10 --skip-task-definition
+```
+
 ## Example of create
 
 escpresso can create service by `service_definition` JSON file and `task_definition`.