Merge pull request #1 from DanielVenturini/colordiff

 - add download and install colordiff to Mac and Linux.

Author: DanielVenturini

Makefile

@@ -1,5 +1,6 @@
 
 PREFIX ?= /usr/local
+SO := $(shell uname)
 
 install: npm-diff
 	cp $< $(PREFIX)/bin/$<
@@ -9,3 +10,15 @@ uninstall:
 
 .PHONY: install uninstall
 
+colordiff_linux:
+	apt-get install colordiff --allow-unauthenticated -y
+
+colordiff_mac:
+	brew install colordiff
+
+colordiff:
+ifeq ($(SO), Linux)
+	make colordiff_linux
+else
+	make colordiff_mac
+endif

README.md

@@ -34,6 +34,12 @@ $ npm-diff intersect 0.0.0 0.1.0 | less
 $ npm-diff intersect 0.0.0 0.1.0 | colordiff | less -R
 ```
 
+If you don't have [colordiff](http://www.colordiff.org), and want to use it (on the Linux, use sudo; in the Mac, don't use):
+
+```bash
+$ make colordiff
+```
+
 ## Sponsors
 
 This module is proudly supported by my [Sponsors](https://github.com/juliangruber/sponsors)!