Handle not found with required

[quexpl]

Fixes #82

[TwelveNights]

One question I have about your implementation is that, if the resource is a nested resource, is there a case in which we don't care if the parent exists? It seems to me that this "nested resource" would not be really nested if the parent ends up being nil.

I guess the issue is that we don't know if a resource is a parent or not unless we use another keyword, though.

Anyways, great PR :)

[quexpl]

I've explained it a bit in related issue #82

[cpjk]

@quexpl Hey! I'm no longer actively working in Elixir, so I'm not actively maintaining this project. I added a notice to the README, but it was committed the same day you opened this PR 🤦 . Sorry to take so long to look at this.

This PR looks good to me, but I haven't tested it!

How would you feel about me adding you as a maintainer? Like I said, I'm not actively maintaining this project, so I would be grateful to have you take it over!