Update social-media.csv (#328)
Update social-media.csv (#328)

Added Billa Hamilton, Tracy Jones, Pip Brown, and Erika Hipwell in alphabetical order
emilyytlin/openpowerlifting,emilyytlin/openpowerlifting,emilyytlin/openpowerlifting,emilyytlin/openpowerlifting,emilyytlin/openpowerlifting