When Rachel Bertsche first moves to Chicago, she’s thrilled to finally share a zip code, let alone an apartment, with her boyfriend. But shortly after getting married, Bertsche realizes that her new life is missing one thing: friends. Sure, she has plenty of BFFs—in New York and San Francisco and Boston and Washington, D.C. Still, in her adopted hometown, there’s no one to call at the last minute for girl talk over brunch or a reality-TV...