feat: login service and implement database storage

database/staff/model.go

@@ -0,0 +1,11 @@
+package staffmodel
+
+import (
+	"github.com/google/uuid"
+)
+
+type Staff struct {
+	ID       uuid.UUID `gorm:"type:uuid;primaryKey" json:"id"`
+	Email    string    `gorm:"unique,not null" json:"email"`
+	Password string    `gorm:"not null" json:"password"`
+}