Add yumda (tool) somewhere

[mhart]

Hey hey – I know I could just add this myself, but wanted to open it up for discussion.

So https://github.com/lambci/yumda is basically a (large) collection of yum packages that have been recompiled for a Lambda /opt environment – that is, you can use it to install binaries and libraries in a way that you can then zip up into a layer. Much more straightforward than having to figure out how to compile any of these packages yourself.

I'd like to add a link to it, but it's not immediately clear where I'd add it. I could just it under the How to create and use section with a little explanation? Or do you think a new/separate section would be better?

[mthenw]

Hey, yeah, adding it under How to create and use Lambda Layers? totally makes sense :)