Upgrade to Angular 4

Author: jhades

README.md

@@ -72,8 +72,15 @@ Then change directory to the folder 01-getting-started-with-angular2, where you
 On the command line run the following:
 
  npm install
+
+If you prefer the Yarn package manager, you can also run:
+
+ yarn
+
+Although nom install would also work, its recommended to use Yarn to install the course dependencies. Yarn has the big advantage that if you use it you will be
+installing the exact same dependencies than I installed in my machine, so you wont run into issues caused by semantic versioning updates.
 
-This should take a couple of minutes. If there are issues, please post the complete error message in the Questions section of the course, i'm there to help. If you have node 6 this should go smoothly. 
+This should take a couple of minutes. If there are issues, please post the complete error message in the Questions section of the course.
 
 # Starting the development server