chore(docs): update documentation for #404

docs/resources/gateway.md

@@ -16,6 +16,12 @@ Network gateways connect SDN Private Networks to external IP networks.
 // Create router for the gateway
 resource "upcloud_router" "this" {
   name = "gateway-example-router"
+
+  # UpCloud Network Gateway Service will add a static route to this router to ensure gateway networking is working as intended.
+  # You need to ignore changes to it, otherwise TF will attempt to remove the static routes on subsequent applies
+  lifecycle {
+    ignore_changes = [static_route]
+  }
 }
 
 // Create network for the gateway

docs/resources/router.md

@@ -29,12 +29,28 @@ resource "upcloud_router" "my_example_router" {
 
 - `name` (String) Name of the router
 
+### Optional
+
+- `static_route` (Block Set) A collection of static routes for this router (see [below for nested schema](#nestedblock--static_route))
+
 ### Read-Only
 
 - `attached_networks` (List of String) A collection of UUID representing networks attached to this router
 - `id` (String) The ID of this resource.
 - `type` (String) The type of router
 
+<a id="nestedblock--static_route"></a>
+### Nested Schema for `static_route`
+
+Required:
+
+- `nexthop` (String) Next hop address. NOTE: For static route to be active the next hop has to be an address of a reachable running Cloud Server in one of the Private Networks attached to the router.
+- `route` (String) Destination prefix of the route.
+
+Optional:
+
+- `name` (String) Name or description of the route.
+
 ## Import
 
 Import is supported using the following syntax: