modify how to contribute

README.md

@@ -32,6 +32,13 @@ build the apk file youself [here](https://github.com/NetEase/Emmagee/wiki/How-to
 3. Select a target process 
 4. Click Start button
 
+Meanwhile you'd better follow the rules below
+
+* It's *NOT* recommended to submit a pull request directly to Dagger's `master` branch. `develop` branch is more appropriate
+* Follow common Java coding conventions
+* Put all Java class files under *com.netease* package
+* Add the following [license](#license) in each Java class file
+
 And Enjoy!
 
 If you want to stop the test, just go back to Emmagee and click Stop button.