Add the note forked from gogs (#590)

* add the note forked from gogs

* make the sentence simple

README.md

@@ -19,7 +19,7 @@
 
 ## Purpose
 
-The goal of this project is to make the easiest, fastest, and most painless way of setting up a self-hosted Git service. With Go, this can be done with an independent binary distribution across **all platforms** that Go supports, including Linux, macOS, and Windows on x86, amd64, ARM and PowerPC architectures. Want to try it before doing anything else? Do it [online](https://try.gitea.io/)!
+The goal of this project is to make the easiest, fastest, and most painless way of setting up a self-hosted Git service. With Go, this can be done with an independent binary distribution across **all platforms** that Go supports, including Linux, macOS, and Windows on x86, amd64, ARM and PowerPC architectures. Want to try it before doing anything else? Do it [online](https://try.gitea.io/)! This project is [forked](https://blog.gitea.io/2016/12/welcome-to-gitea/) from [Gogs](https://gogs.io).
 
 ## Notes