The board may appoint a general manager and such other persons who are necessary to make the authority succeed. The general manager shall hold office at the pleasure of the board. The general manager shall manage the properties and business of the authority and the employees thereof, subject to the general control of the board, shall direct the enforcement of all resolutions, rules and regulations of the board, and shall perform such other duties as may be prescribed by the board. No discrimination shall be made in any appointment or promotion because of race, creed, color, disability, religious or political affiliations.