Pull request with correct commits history (tango-controls#23)

* Update CONTRIBUTE.md

Author: Ingvord

CONTRIBUTE.md

@@ -4,5 +4,19 @@
 
 - fork
 - clone fork
+- start a new branch `git branch my-contrib`
+- switch to the new branch `git checkout my-contrib`
 - do changes
-- create pull request
+- commit&push
+- create pull request
+
+# To update forked repo localy
+
+Before submitting a new pull request
+
+- git fetch upstream
+- git rebase upstream/master
+
+_OR_
+
+- git pull --rebase upstream master