Better test and document design-tokens subcommand

I've got an example figma file to use to demonstrate and test against.

lukasoppermann/design-tokens#238

In the documentation I list out the problems (mostly the result of lack
of API support from Figma).

Author: ccouzens

.gitignore

@@ -1,4 +1,3 @@
 /target
 /node_modules
-/example-file.json
 /private

Makefile

@@ -1,15 +1,26 @@
+.DEFAULT_GOAL := all
+
+example-figma-files = \
+example-figma-files/design-tokens-for-figma.json
+
+example-output-files = \
+src/design_tokens/example-output.json
+
 # https://www.figma.com/file/2MQ759R5kJtzQn4qSHuqR7/Design-Tokens-for-Figma
-example-file.json :
+example-figma-files/design-tokens-for-figma.json :
 	curl -sH "X-Figma-Token: ${FIGMA_TOKEN}" \
     'https://api.figma.com/v1/files/2MQ759R5kJtzQn4qSHuqR7' \
 	| jq > $@
 
+src/design_tokens/example-output.json : example-figma-files/design-tokens-for-figma.json
+	cargo run -- design-tokens < $< > $@
+
 .PHONY : all
-all : example-file.json
+all : $(example-figma-files) $(example-output-files)
 
 .PHONY : clean
 clean :
-	rm -f example-file.json
+	rm -f $(example-figma-files) $(example-output-files)
 
 .PHONY : cleanAll
 cleanAll : clean

README.md

@@ -6,9 +6,9 @@ An experiment to see what can be achieved with the
 All commands require an API file to be provided on `stdin`.
 
 ```bash
-cargo run --release -- design-tokens < example-file.json
+cargo run -- design-tokens < example-figma-files/design-tokens-for-figma.json
 # or
-curl -sH "X-Figma-Token: ${FIGMA_TOKEN}" https://api.figma.com/v1/files/2MQ759R5kJtzQn4qSHuqR7 | cargo run --release -- design-tokens
+curl -sH "X-Figma-Token: ${FIGMA_TOKEN}" https://api.figma.com/v1/files/2MQ759R5kJtzQn4qSHuqR7 | cargo run -- design-tokens
 ```
 
 ## Design tokens
@@ -23,3 +23,5 @@ cargo run --release -- design-tokens < example-file.json
 Due to limitations with the Figma API, I do not recommend this subcommand. Some
 basic information cannot be obtained through the API such as colour token values
 or font information. I do recommend the plugin.
+
+[Read more](src/design_tokens/README.md)