Add admin-route & dropdown-menu. Add clear-cache & create-code. Adjustments for activation-code and user models. Add sweet-alert for admin-tools.

models/code.go

@@ -1,6 +1,8 @@
 package models
 
 type ActivationCode struct {
-	Code string
-	Used bool
+	Code            string `gorm:"primary_key"`
+	UserRole        Role
+	UsedForUsername string
+	UsedFor         User `gorm:"foreignKey:UsedForUsername"`
 }