[flybot] Fly CLI docs update

flyctl/cmd/fly_mpg.md

@@ -13,6 +13,7 @@ fly mpg [command] [flags]
 * [create](/docs/flyctl/mpg-create/)	 - Create a new Managed Postgres cluster
 * [databases](/docs/flyctl/mpg-databases/)	 - Manage databases in a managed postgres cluster
 * [destroy](/docs/flyctl/mpg-destroy/)	 - Destroy a managed Postgres cluster
+* [detach](/docs/flyctl/mpg-detach/)	 - Detach a managed Postgres cluster from an app
 * [list](/docs/flyctl/mpg-list/)	 - List MPG clusters.
 * [proxy](/docs/flyctl/mpg-proxy/)	 - Proxy to a MPG database
 * [restore](/docs/flyctl/mpg-restore/)	 - Restore MPG cluster from backup.

flyctl/cmd/fly_mpg_detach.md

@@ -0,0 +1,28 @@
+Detach a managed Postgres cluster from an app. This command will remove the attachment record linking the app to the cluster.
+Note: This does NOT remove any secrets from the app. Use 'fly secrets unset' to remove secrets.
+
+## Usage
+~~~
+fly mpg detach <CLUSTER ID> [flags]
+~~~
+
+## Options
+
+~~~
+  -a, --app string      Application name
+  -c, --config string   Path to application configuration file
+  -h, --help            help for detach
+~~~
+
+## Global Options
+
+~~~
+  -t, --access-token string   Fly API Access Token
+      --debug                 Print additional logs and traces
+      --verbose               Verbose output
+~~~
+
+## See Also
+
+* [fly mpg](/docs/flyctl/mpg/)	 - Manage Managed Postgres clusters.
+