There shall be a council of five members, which shall consist of the mayor as ex officio councilman at large and one councilman from each of the four wards of the city as the wards are now constituted or as they may hereafter be constituted by ordinance. The electors shall elect them as provided in this charter for a term of three years and until their successors have been elected and take office. Only qualified electors of the city shall be qualified for the office of mayor and ex officio councilman at large. Only qualified electors residing in the city and in the wards from which they are respectively elected shall be qualified for the offices of councilmen from the wards; and removal of such councilman from the ward from which he was elected to another ward shall disqualify him from completing the term for which he was elected. Neither the mayor nor any other councilman may hold any office or position in the city government by appointment by the city manager.