You Now Have A Way to Force Eevee Evolve into the One You Like in Pokemon Go
The way is kinda simple. Choose the Eevee you want to evlove and rename that Eevee by clicking the "pencil" tool. Nicknaming your Eevee either Rainer, Pyro or Sparky, your Eevee will evolve into that desired Eeveelution! For short, it is
Sparky = Jolteon
Rainer = Vaporeon
Pyro = Flareon
A lot of redditors said they used this method and it worked perfectly. Here's a small tips from OP smithnigel - it is recommended to name your Eevee with your intended evolution name, then close and restart the app to confirm the name went through on the servers.
There's also a feedback says you can't obtain the same one twice in a row.
We don't know whether it is a bug or not but the video below also proves that theory.