Add a top-level Makefile.

This is primarily to automate launching jaeger in docker for easier viewing of traces.

Makefile

@@ -0,0 +1,25 @@
+SHELL := bash
+.ONESHELL:
+.SHELLFLAGS := -eu -o pipefail -c
+.DELETE_ON_ERROR:
+MAKEFLAGS += --warn-undefined-variables
+MAKEFLAGS += --no-builtin-rules
+
+ifeq ($(origin .RECIPEPREFIX), undefined)
+  $(error This Make does not support .RECIPEPREFIX. Please use GNU Make 4.0 or later)
+endif
+.RECIPEPREFIX = >
+
+.PHONY: build
+build: target/debug/toy
+
+.PHONY: clean
+clean:
+> cargo clean
+
+target/debug/toy:
+> cargo build
+
+.PHONY: jaeger
+jaeger:
+> docker run -d --rm -p 6831:6831/udp -p 6832:6832/udp -p 16686:16686 -p 14268:14268 jaegertracing/all-in-one:latest