In San Francisco, in 1977, Harvey Milk did the same thing in San Francisco, getting gay bars and restaurants to join an AFL/CIO boycott against Coors. As a result of an ensuing boycott of Coors in California gay bars/restaurants, Coors Lite dropped from #1 in California to #2, then #3, and finally bottomed out in fourth place before the panicked company began to make amends to the gay community.
The Hollywood Reporter reviewed the film here. Below is IMDb's synopsis of Pride:
Its the summer of 1984 Margaret Thatcher is in power and the National Union of Mineworkers (NUM) is on strike. At the Gay Pride March in London, a group of gay and lesbian activists decides to raise money to support the families of the striking miners. But there is a problem. The Union seems embarrassed to receive their support.
But the activists are not deterred. They decide to ignore the Union and go direct to the miners. They identify a mining village in deepest Wales and set off in a mini bus to make their donation in person. And so begins the extraordinary story of two seemingly alien communities who form a surprising and ultimately triumphant partnership.