Growth Chart - Rails Developer

Hi,

I’m trying to build an exhaustive list of Rails concepts that one would learn over a period of time, to become a Rails ‘ninja’ .
The list is on Github

I’m trying to pair concepts with experience level ( a rough estimate of what concept you should know at what experience level )

This should help as a learning ladder for a Rails developer, at any stage, to move on to the next stage.

Would appreciate help in growing and maintaining this list.

Thanks.