diff -r c28f7e417146 -r bce8b17415ae gondole.go
--- a/gondole.go	Fri Apr 07 15:31:39 2017 +0200
+++ b/gondole.go	Fri Apr 07 15:32:29 2017 +0200
@@ -4,6 +4,7 @@
 import (
 	"github.com/sendgrid/rest"
 	"fmt"
+	"errors"
 )
 
 const (
@@ -14,6 +15,10 @@
 	NoRedirect = "urn:ietf:wg:oauth:2.0:oob"
 )
 
+var (
+	ErrAlreadyRegistered = errors.New("App already registered")
+)
+
 // prepareRequest insert all pre-defined stuff
 func (g *Gondole) prepareRequest(what string) (req rest.Request) {
 	endPoint := APIEndpoint + fmt.Sprintf("/%s/", what)