Migration system & fix ssh key table constraint

internal/models/user.go

@@ -16,7 +16,7 @@ type User struct {
 	GiteaID   string
 
 	Gists   []Gist   `gorm:"constraint:OnUpdate:CASCADE,OnDelete:CASCADE;foreignKey:UserID"`
-	SSHKeys []SSHKey `gorm:"foreignKey:UserID"`
+	SSHKeys []SSHKey `gorm:"constraint:OnUpdate:CASCADE,OnDelete:CASCADE;foreignKey:UserID"`
 	Liked   []Gist   `gorm:"many2many:likes;constraint:OnUpdate:CASCADE,OnDelete:CASCADE"`
 }