Bijection is split into a bunch of submodules: bijection-guava, bijection-json, bijection-netty, etc, all of which depend on bijection-core. 

All of these lazy vals are separate modules:

https://github.com/twitter/bijection/blob/develop/project/Build.scala#L187

and each lazy val needs to be added to the aggregate project:

https://github.com/twitter/bijection/blob/develop/project/Build.scala#L106

@johnynek is asking you to create a new lazy val for `bijectionJodaTime`, rather than adding the dependency to `bijection-core`.