update readme

Author: PeterDaveHello

README.md

@@ -1,2 +1,18 @@
 # ColorEchoForShell
 Make echo colorful with easier method.
+
+## Installation
+
+* Download the script and add one line to your shell rc: `. colorEcho.sh` or run `. colorEcho.sh` directly.
+
+## Usage
+
+* echo.Cyan CyanExample
+* echo.ULCyan UnderLineCyanExample
+* echo.BoldCyan BoldCyanExample
+* echo.BoldULCyan BoldUnderLineCyanExample
+
+## Supported colors
+
+* See [color table](https://cdn.rawgit.com/PeterDaveHello/ColorEchoForShell/master/table.txt)
+