Add Social Media Links for Mostlychris

[mostlychris]

Problem/Motivation

Add YouTube channel mostlychris
Add Twitter @mostlychris2

Proposed changes

Add YouTube channel mostlychris
Add Twitter handle @mostlychris2

Youtube Channel Link: https://www.mostlychris.com/c/mostlychris

[spencer1573]

PR #426 resolves this issue. Please let me know if you have any questions. thanks!