Update index.ngdoc

[JeremyLikness]

Added a link to 10 reasons to use and online courses for Angular

[mary-poppins]

I'm sorry, but I wasn't able to verify your Contributor License Agreement (CLA) signature. CLA signature is required for any code contributions to AngularJS.

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[mary-poppins]

CLA signature verified! Thank you!

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[IgorMinar]

thanks