fix(self-hosted): allow configuring supavisor tenant db_host via env var (#41273)

docker/docker-compose.yml

@@ -627,6 +627,7 @@ services:
     environment:
       PORT: 4000
       POSTGRES_PORT: ${POSTGRES_PORT}
+      POSTGRES_HOST: ${POSTGRES_HOST}
       POSTGRES_DB: ${POSTGRES_DB}
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
       DATABASE_URL: ecto://supabase_admin:${POSTGRES_PASSWORD}@${POSTGRES_HOST}:${POSTGRES_PORT}/_supabase

docker/volumes/pooler/pooler.exs

@@ -8,7 +8,7 @@
 
 params = %{
   "external_id" => System.get_env("POOLER_TENANT_ID"),
-  "db_host" => "db",
+  "db_host" => System.get_env("POSTGRES_HOST") || "db",
   "db_port" => System.get_env("POSTGRES_PORT"),
   "db_database" => System.get_env("POSTGRES_DB"),
   "require_user" => false,