removed -u as per lesson today (Padova September 2017)

_episodes/03-sharing.md

@@ -99,7 +99,7 @@ will have to "push" our local changes to the GitHub repository. We do this using
 `git push` command:
 
 ~~~
-$ git push -u origin master
+$ git push origin master
 ~~~
 {: .bash}
 ~~~
@@ -286,4 +286,4 @@ this by entering the `ls` command.
 
 When we begin collaborating on more complex projects, we may have to consider more aspects of git functionality, but 
 this should be a good start. In the next section, we can look more closely at collaborating and using GitHub pages to
-create a website for our project.
+create a website for our project.