atom/metrics — pull request #33 by benogle (2014-11-05 20:57:39+00:00)
Title: Add weekly cohort in addition to start date

This should allow us to do the 28 days later, and generally see retention on a week by week basis.

Format is `yyyymmdd,week#`. Weeks are given a number starting from `1` for jan 1 in 2014. For each year week numbers increment by `100`. So jan 1 2015 is `101`, week 52 in 2015 will be `152`. The GA matchers for using this data are really flexible (regex!), so they should be easy to match either monthly or weekly, depending on our needs.