Add customer domain Traefik routing

database/migrations/004_instance_custom_domain.sql

@@ -0,0 +1,4 @@
+-- Add an optional customer-owned domain for Traefik routing.
+ALTER TABLE instances
+    ADD COLUMN IF NOT EXISTS custom_domain VARCHAR(253) NULL AFTER name,
+    ADD UNIQUE KEY IF NOT EXISTS uq_instances_custom_domain (custom_domain);

database/schema.sql

@@ -71,6 +71,7 @@ CREATE TABLE IF NOT EXISTS instances (
     id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
     owner_user_id BIGINT UNSIGNED NOT NULL,
     name VARCHAR(120) NOT NULL,
+    custom_domain VARCHAR(253) NULL,
     plan ENUM('s', 'm', 'l') NOT NULL DEFAULT 's',
     billing_period ENUM('monthly', 'yearly') NOT NULL DEFAULT 'monthly',
     price_gross_cents INT UNSIGNED NOT NULL DEFAULT 0,
@@ -91,6 +92,7 @@ CREATE TABLE IF NOT EXISTS instances (
     updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
     PRIMARY KEY (id),
     UNIQUE KEY uq_instances_container_name (container_name),
+    UNIQUE KEY uq_instances_custom_domain (custom_domain),
     UNIQUE KEY uq_instances_port (port),
     CONSTRAINT fk_instances_owner FOREIGN KEY (owner_user_id) REFERENCES users (id)
         ON UPDATE CASCADE ON DELETE RESTRICT