Adding documentation
diff --git a/openstack/db/v1/instances/doc.go b/openstack/db/v1/instances/doc.go
index 98a1bb3..dc5c90f 100644
--- a/openstack/db/v1/instances/doc.go
+++ b/openstack/db/v1/instances/doc.go
@@ -1 +1,7 @@
+// Package instances provides information and interaction with the instance API
+// resource in the OpenStack Database service.
+//
+// A database instance is an isolated database environment with compute and
+// storage resources in a single tenant environment on a shared physical host
+// machine.
package instances