public override void Up()
{
DropForeignKey("DiffLines", "Hunk_Id", "FileChanges");
DropIndex("DiffLines", new[] { "Hunk_Id" });
AddForeignKey("DiffLines", "ChangeId", "FileChanges", "Id", cascadeDelete: true);
CreateIndex("DiffLines", "ChangeId");
DropColumn("DiffLines", "Hunk_Id");
}