SHANGHAI, Aug 7 (Reuters) - Tencent Holdings-backed Chinese education firm VIPKid said on Saturday it would stop selling classes taught by foreign-based tutors to students in China with immediate effect to comply with new rules announced for the country's private education sector. China last month issued rules barring curriculum-based tutoring for profit, aiming to ease financial pressures that have contributed to low birth rates but have left private education firms facing significant business impact. The rules also ban companies from employing foreign-based tutors, aiming to stop long-distance lessons for Chinese students. Beijing-based VIPKid is an online education platform that connects...