Fix options help in README.md in-place

Makefile

@@ -67,14 +67,10 @@ js/node_modules/webpack:
 	cd js && \
 	npm install
 
-README.md: README.md.in
-	git log --pretty=format:' * %aN' | \
-		grep -v 'S.*ren L. Hansen' | \
-		grep -v 'Iwasaki Yudai' | \
-		sort -u > contributors.txt.tmp
+README-options:
 	./gotty --help | sed '1,/GLOBAL OPTIONS/ d' > options.txt.tmp
-	sed -f README.md.sed < $< > $@
-	rm contributors.txt.tmp options.txt.tmp
+	sed -f README.md.sed -i README.md
+	rm options.txt.tmp
 
 tools:
 	go get github.com/mitchellh/gox