Summary:
Added details about how IOS Native Modules can be initialized & registered manually with custom initializers so that dependencies can be injected to said modules.
Please let me know if there is a more appropriate place to detail this in the documentation or this is in fact detailed elsewhere; I also believe we do not have documentation on how to do the equivalent on Android, however it is a bit more obvious as the automatic MACRO registration mechanism does not exist on Android and modules need to be initialized manually anyway. As I currently understand there isn't currently any documentation detailing this apart from comments in the source.
Please let me know if you would require any style changes (variable names etc), to be more en-keeping with the rest of the documentation.
Closes https://github.com/facebook/react-native/pull/8406
Differential Revision: D3843018
Pulled By: javache
fbshipit-source-id: 5f4001df32d1ddc00a9dacc4fc99b63b408f1536
66abc86c9a