Finish DB docs for Rackspace
diff --git a/rackspace/db/v1/instances/requests.go b/rackspace/db/v1/instances/requests.go
index cfebd5d..7a1a4f8 100644
--- a/rackspace/db/v1/instances/requests.go
+++ b/rackspace/db/v1/instances/requests.go
@@ -6,6 +6,10 @@
 	"github.com/rackspace/gophercloud/rackspace/db/v1/backups"
 )
 
+// GetDefaultConfig lists the default configuration settings from the template
+// that was applied to the specified instance. In a sense, this is the vanilla
+// configuration setting applied to an instance. Further configuration can be
+// applied by associating an instance with a configuration group.
 func GetDefaultConfig(client *gophercloud.ServiceClient, id string) ConfigResult {
 	var res ConfigResult
 
@@ -17,6 +21,9 @@
 	return res
 }
 
+// AssociateWithConfigGroup associates a specified instance to a specified
+// configuration group. If any of the parameters within a configuration group
+// require a restart, then the instance will transition into a restart.
 func AssociateWithConfigGroup(client *gophercloud.ServiceClient, instanceID, configGroupID string) UpdateResult {
 	reqBody := map[string]string{
 		"configuration": configGroupID,
@@ -32,6 +39,7 @@
 	return res
 }
 
+// ListBackups will list all the backups for a specified database instance.
 func ListBackups(client *gophercloud.ServiceClient, instanceID string) pagination.Pager {
 	pageFn := func(r pagination.PageResult) pagination.Page {
 		return backups.BackupPage{pagination.SinglePageBase(r)}
@@ -39,6 +47,9 @@
 	return pagination.NewPager(client, backupsURL(client, instanceID), pageFn)
 }
 
+// DetachReplica will detach a specified replica instance from its source
+// instance, effectively allowing it to operate independently. Detaching a
+// replica will restart the MySQL service on the instance.
 func DetachReplica(client *gophercloud.ServiceClient, replicaID string) DetachResult {
 	var res DetachResult