Add mack video to README

[MrPowers]

Awesome video should be added to the README: https://www.youtube.com/watch?v=qRR5n6T2N_8

[Triamus]

I will do that some time this week. Will add it as new section Videos under Community header if that's ok.

[MrPowers]

Thanks @Triamus. Assigned the issue to you!