Creating custom auth component is complex from docs and examples

The documentation is step by step but fails to fully cover the code required.

https://akveo.github.io/nebular/docs/auth/custom-auth-components#login-component-extension

The example link given at the end of the article is dead.

Playground example is quite mixed up and it is very easy to make mistakes in routing module when custom component (extension of NbLogin etc) is involved.

For example, in [this repo](https://github.com/akveo/nebular/tree/v2.0.0/src/framework/auth) - all components are given with source. How should one follow components from @nebular node package?

It will be helpful to have one dedicated example for custom component development.