Improve clarity of instructions

[brylie]

I have trouble with reading for meaning. In case other people have the same struggles, perhaps these small changes will prove helpful.

[brylie]

Converted to draft while I work through the instructions. There still seems to be some missing context that may be tacit knowledge to experienced Cabbage or Rack developers.

For example, after building the template plugin, should I copy it to ~/.Rack/plugins-v1/? Similarly, the current instructions say to cd into Rack/plugins, but the folder on my computer is ~/.Rack/plugins-v1/.

Some explanation of "why" could help things along, such as

• why do we build the template plugin?
• why do we clone CabbageRack within ~/.Rack/plugins-v1/

[rorywalsh]

You might have seen my other post about the new build system. It's probably best to wait till that is complete before doing too much work here. Needless to say, it should hopefully remove any sense of confusion about how to get this up and running.