Governing bodies of municipalities issuing bonds under the provisions of this act [5- 3-1 to 5-3-8 N.M. Stat. Ann.], may authorize the issuance thereof by ordinance adopted by the affirmative vote of two-thirds of all the members of said governing bodies, at either regular or special meeting called for that purpose, wherein the necessity thereof shall be declared and, when issued, shall be signed by the mayor or other executive head and attested by the clerk of said governing body, with the seal of said municipality affixed thereto.