Merge pull request #120 from arokem/adds_doc_video [skip ci]

Adds link to NH video.

Author: oesteban

docs/index.rst

@@ -11,3 +11,12 @@ Contents
     api
     changes
     roadmap
+
+
+The overall philosophy of the NiPreps and some examples are explained in this video:
+
+.. raw:: html
+
+    <div style="position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; height: auto;">
+        <iframe src="//www.youtube.com/embed/J_ZwPN8gYpM" frameborder="0" allowfullscreen style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"></iframe>
+    </div>