Georgia Code Title 36. Local Government § 36-38-23

If any municipal corporation availing itself of this article desires to provide a sinking fund for the redemption of such new bonds, the authorities may pass all ordinances necessary for that purpose and create a commission for the management of such sinking fund and its proper use and application. The commission shall be composed of not less than three nor more than five residents of the municipal corporation. The ordinance or ordinances providing for the sinking fund and for the commission, along with its management and application, the mode of appointing the members thereof, and its duties, shall have the force and effect of law and shall be held and considered as part of the contract between the municipal corporation and the acceptors or holders of the new bonds.