Update spin provision command with user option

docs/content/docs/4.command-reference/provision.md

@@ -15,7 +15,7 @@ Provision and set up your inventory of servers. This command requires you have
 label: Usage for "spin provision"
 ---
 ```bash
-spin provision
+spin provision [-u|--user <user>]
 ```
 ::
 
@@ -26,5 +26,11 @@ Before you execute this command, you should have the following completed:
 - The `.spin.yml` file should be configured 
 - The `.spin-inventory.ini` file should properly be configured
 
+## Options
+The following options are available to set when running this command.
+| Option | Short | Default | Description |
+| --- | --- | --- | --- |
+| `--user` | `-u` | `root` | The user to SSH into the server with. |
+
 ## Learn More
 [Configuring your servers for "spin provision" →](/docs/guide/preparing-your-servers-for-spin)