Append the number of commits since the last tag to the version (#17)

Co-authored-by: Jim Weinert <jweinert@digitalocean.com>

Makefile

@@ -1,9 +1,13 @@
 .PHONY: build test test-short vendor
 
 latest_tag := $(shell git describe --tags --abbrev=0)
-commits_since_tag := $(shell git rev-list ${latest_tag}..HEAD --count)
-# TODO: append commits_since_tag to the version if commits_since_tag is not 0
 version := ${latest_tag}
+
+commits_since_tag := $(shell git rev-list ${latest_tag}..HEAD --count)
+ifneq (${commits_since_tag}, 0)
+	version = ${latest_tag}-${commits_since_tag}
+endif
+
 go_ldflags := "-X main.Version=${version}"
 
 build: vendor