diff --git a/models/contract.go b/models/contract.go
index fb2be07..536d31c 100644
--- a/models/contract.go
+++ b/models/contract.go
@@ -1,11 +1,14 @@
 package models
 
-import "github.com/jinzhu/gorm"
+import (
+	"github.com/jinzhu/gorm"
+	"github.com/lib/pq"
+)
 
 type Contract struct {
 	gorm.Model
 	Name          string
-	DeviceID      []uint
+	DeviceIDs     pq.Int64Array `gorm:"type:integer[]"`
 	BuyerID       uint
 	Status        string
 	BlockchainID  string