When I see the version value in in schema.rb of a Rails 4.2 application as below, it looks like 2015 is the year, 04 is the month (April), and 27 is the day. But what is 115639 then?
ActiveRecord::Schema.define(version: 20150427115639) do
Is equivalent to:
04/25/2015 @ 2:00am (UTC)
The schema version comes from the timestamp of the most recent migration. That in turn is the concatenated digits of the date and time when the migration was generated.
20150427115639 comes from "2015-04-27 11:56:39".