Re-enable gce ingress.

terraform/main.tf

@@ -1,3 +1,4 @@
+# TODO: put IP address ranges into variables
 terraform {
   backend "gcs" {
     bucket = "tf-state-4b00"
@@ -50,8 +51,8 @@ variable "ingress_type" {
   default     = "gateway"
 
   validation {
-    condition     = contains(["gateway", "nginx"], var.ingress_type)
-    error_message = "Must be either \"gateway\" or \"nginx\"."
+    condition     = contains(["gateway", "nginx", "gce"], var.ingress_type)
+    error_message = "Must be either \"gateway\", \"nginx\", or \"gce\"."
   }
 }