Tweak Makefile (#436)

Create a top level `pgroll` rule.

Add separate `clean` and `generate` rules.

Author: ryanslade

Makefile

@@ -1,10 +1,16 @@
-.PHONY: generate lint examples test
+.PHONY: pgroll generate format lint examples test
 
-generate:
+pgroll:
+	go build
+
+clean:
+	go clean
+
+format:
 	# Format JSON schema
-	docker run --rm -v $$PWD/schema.json:/mnt/schema.json node:alpine npx prettier /mnt/schema.json --parser json --tab-width 2 --single-quote --trailing-comma all --no-semi --arrow-parens always --print-width 120 > schema.json.tmp
-	mv schema.json.tmp schema.json
+	docker run --rm -v $$PWD/schema.json:/mnt/schema.json node:alpine npx prettier /mnt/schema.json --parser json --tab-width 2 --single-quote --trailing-comma all --no-semi --arrow-parens always --print-width 120 --write
 
+generate: format
 	# Generate the types from the JSON schema
 	# Temporarily use the `surjection/go-jsonschema` image because we need https://github.com/omissis/go-jsonschema/pull/220
 	# Use the official `omissis/gojsonschema` image once 0.17.0 is released.