Add how to contribute and mirror notice

README.md

@@ -1,8 +1,11 @@
 # AchievementInfo
 This is an Elderscrolls Online addon. [See all details and the download @ESOUI](http://www.esoui.com/downloads/info350-AchievementInfo.html#info).
 
-Test
-
-## Why is it at Github?
+## Why is this a public project?
 In case I quit or pause playing TESO and cannot maintain this addon, feel free to contribute to keep this up to date and running.
-I'll still be active on Github and be able to update the ESOUI page.
+I'll still be available here and be able to update the ESOUI page.
+
+## How to contribute?
+Github is a mirror. Please contribute at https://git.f-brinker.de/fbrinker/elderscrolls-addon-achievementInfo - You can login with your Github account (OAuth2).
+
+Then, create a fork of the repository, do what you have to do and create a pull-request afterwards. Feel free to contact me any time.