Added UserActivation struct

modules/structs/userActivation.go

@@ -0,0 +1,13 @@
+package structs
+
+import (
+	"time"
+)
+
+// UserActivation represents a user activation
+// swagger:model
+type UserActivation struct {
+	Id      string
+	UserId  string
+	Expires time.Time
+}