Any person now serving as an elected superintendent of education in this state may become a member of the Teachers’ Retirement System of Alabama within 90 days after the ratification of an amendment to the Constitution of Alabama 1901 allowing elected superintendents of education to participate in the Teachers’ Retirement System, subject to such rules and regulations as may be promulgated by the Board of Control of said system. Any person hereafter elected to serve as superintendent of education shall be deemed to be a “teacher” as defined in Section 16-25-1 and shall be entitled to the benefits thereof. The employer cost for coverage of such elected superintendents shall be paid as for other school employees. Provided further, that such elected superintendents shall be entitled to purchase prior service credit as a teacher or superintendent in such system under such rules, regulations and provisions of law that govern the purchase of such prior service credit, from time to time, by teachers.