The mayor of Pittsburgh late Tuesday conceded in a primary race to challenger Ed Gainey, a Democrat who currently holds a seat in the state House of Representatives. Mayor Bill Peduto, a Democrat, said he called Gainey and congratulated him. “Wishing him well. Thank you Pittsburgh for the honor of being your Mayor these past 8 years. I will remain forever grateful,” Peduto said in a tweet. Gainey told an election night party that “one person can’t change a city.” “A city is changed with all of us. A city is changed when we all come together to improve the quality of life for everybody. That’s why I ran for mayor, because I believe that we can have a city for all. And we will work hard—not just I as mayor but we as community, we as city, will work to build a better city called Pittsburgh for everybody,” he …