Add additional video tutorial reference to documentation. (#921)

* Added additional video tutorial

Added additional link to video tutorial series by Ian Annase. The original tutorial is very low resolution and is hard to follow. The tutorial linked in this commit is entirely in HD and goes further in depth, including examples of possible functionality.

* Update index.rst

Adjusted link formatting.

* Update index.rst

Updated link formatting again because I'm an idiot.

* Update index.rst

Edited formatting to fix missing period and double wording.

docs/index.rst

@@ -9,7 +9,7 @@ Welcome to Spotipy!
 you get full access to all of the music data provided by the Spotify platform.
 
 Assuming you set the ``SPOTIPY_CLIENT_ID`` and ``SPOTIPY_CLIENT_SECRET``
-environment variables (here is a `video <https://youtu.be/3RGm4jALukM>`_ explaining how to do so), here's a quick example of using *Spotipy* to list the
+environment variables (here is a `video <https://youtu.be/3RGm4jALukM>`_ explaining how to do so). For a longer tutorial with examples included, refer to this `video playlist <https://www.youtube.com/watch?v=tmt5SdvTqUI&list=PLqgOPibB_QnzzcaOFYmY2cQjs35y0is9N&index=1>`_. Below is a quick example of using *Spotipy* to list the
 names of all the albums released by the artist 'Birdy'::
 
     import spotipy