--- /dev/null
+/**
+ * Implements hook_schema_alter().
+ */
+function {{ machine_name }}_schema_alter(&$schema) {
+ // Add field to existing schema.
+ $schema['users']['fields']['timezone_id'] = array(
+ 'type' => 'int',
+ 'not null' => TRUE,
+ 'default' => 0,
+ 'description' => 'Per-user timezone configuration.',
+ );
+}