Added test for model.changedAttributes()
command was correct but text not
Merge pull request #2521 from kellyselden/fix-readme-ember-cli

command was correct but text not
Merge pull request #2518 from wecc/model-changed-attributes-test

Added test for model.changedAttributes()
[BUG] Transform `{NaN,Infitity,-Infinity}` to null

https://github.com/emberjs/data/pull/2509#discussion_r20898264

Serializing and Deserializing invalid numeric `JSON` (`NaN`,
`Infinity`, `-Infinity`) should result in `null`.