An Act repealing the act of September 10, 1965 (P.L.511, No.258), entitled "A supplement to the act of May 28, 1915 (P.L.596), entitled 'An act requiring cities of the second class to establish a pension fund for employes of said cities, and regulating the administration and the payment of such pensions,' providing a period during which certain persons may join the pension fund created under the act and providing a means whereby any person who has not received full credit toward his pension for service as a city employe may obtain such credit."