rails/rails — pull request #16361 by JackDanger (2014-07-31 16:57:14+00:00)
Title: [doc] Clarify how the ConnectionHandler works

This makes the implicit description of how connection pooling works a
little more explicit. It converse the examples of a model hierarchy into
actual Ruby code and demonstrates how the key structure of the
database.yml relates to the `establish_connection` method.