Eevee Evolution Trick

Eevee evolves into one of three forms in Pokemon Go, but they do so pretty randomly. If you evolve Eevee in the presence of a gym, the color of the gym should increase your likelihood of getting the evolved form you want -- ie; red gym should evolve into Flareon, yellow into Jolteon, and blue into Vaporeon. Mine just didn't work out as planned.