ember-cli : Add alias for ember test --serve (#6492)

plugins/ember-cli/README.md

 # Ember CLI
 
-**Maintainers:** [BilalBudhani](https://github.com/BilalBudhani), [eubenesa](https://github.com/eubenesa)
+**Maintainers:** [BilalBudhani](https://github.com/BilalBudhani), [eubenesa](https://github.com/eubenesa), [scottkidder](https://github.com/scottkidder]
 
 Ember CLI (https://www.ember-cli.com/)
 
@@ -17,5 +17,6 @@ Alias | Ember-CLI command
 **ein** | *ember init*
 **ei** | *ember install*
 **et** | *ember test*
+**ets** | *ember test --serve*
 **eu** | *ember update*
 **ev** | *ember version*

plugins/ember-cli/ember-cli.plugin.zsh

@@ -10,6 +10,7 @@ alias eh='ember help'
 alias ein='ember init'
 alias ei='ember install'
 alias et='ember test'
+alias ets='ember test --serve'
 alias eu='ember update'
 
 # version