The holiday season has come to life in Union Square in the heart of downtown San Francisco. There’s a big menorah to celebrate Hanukkah, a lighted Christmas tree, an ice rink — and the gentle ringing of small white bells next to red Salvation Army kettles. The bell ringers are there with their kettles in front of Macy’s on Union Square in all weather — driving rain, the pale December sunshine, the chill of late fall — raising money the old-fashioned way.