feat: add refund statuses

backend/app/models/users.go

@@ -448,3 +448,21 @@ func (m *usersModel) BuyPosts(ctx context.Context, userID, postID, price int64)
 	}
 	return nil
 }
+
+func (m *usersModel) RevokePosts(ctx context.Context, userID, postID int64) error {
+	tbl := table.UserPosts
+	stmt := tbl.
+		DELETE().
+		WHERE(
+			tbl.UserID.EQ(Int64(userID)).AND(
+				tbl.PostID.EQ(Int64(postID)),
+			),
+		)
+	m.log.Infof("sql: %s", stmt.DebugSql())
+
+	if _, err := stmt.ExecContext(ctx, db); err != nil {
+		m.log.Errorf("error revoking user post: %v", err)
+		return err
+	}
+	return nil
+}