text: Title: Request: add 'how to seed' to the readme.md
  Body: The readme.md currently reads:
  >Note
  >
  >Use of fully randomized data in tests is quickly a problem for reproducing broken builds. To that purpose, factory_boy provides helpers to handle the random seeds it uses.
  
  however, that is the only mention of the word "seed" in the entire readme, could a bit be added that shows how to actually seed a Faker so multiple runs with the same see yield the same data?