Add basic Makefile to ease packaging

Makefile

@@ -0,0 +1,25 @@
+git_watched_files := $(shell git ls-files)
+extension_files := $(shell find extension -type f -not -name '*.map')
+
+.PHONY: build watch clean package
+
+all: build package
+
+extension.zip: $(extension_files)
+	cd extension && \
+	find . -type f -not -name '*.map' | xargs zip ../extension.zip
+
+sources.zip: $(git_watched_files)
+	git ls-files | xargs zip sources.zip
+
+package: extension.zip sources.zip
+
+build:
+	npm run build
+
+watch:
+	npm run build:watch
+
+clean:
+	rm extension/dist/*;
+	rm extension.zip sources.zip