Git is a distributed version control system.
Git is a free software distributed under the GPL.
Add the thrid line in readme.txt

Git has a mutable index called stage.
Git tracks changes of files.

add info from dev branch

fast forward merge

no ff merge


add info ro master

add from branch feature1

add from branch feature2

add from branch feature3

new line from master

这里是一个最新正式版本，v1.0.0