Louisville Mayor Greg Fischer will sign an executive order this morning that will extend health insurance benefits to the domestic partners of city employees.The change will go into effect on July 1, 2012. According to the Courier-Journal, the city's Human Resources Department estimates that as many as 400 of the city's 5,500 employees will take advantage of the benefits, which would cost about $400,000.The order includes both same-sex and heterosexual couples.Fischer pledged during his campaign for office to take the action if elected.