Taylor Swift celebrated Thanksgiving by taking part in the ‘‘mannequin challenge.’’ The singer-songwriter posted a video on her Instagram account Thursday that shows her posing with pals — and then busting a move — on a sandy beach in Rhode Island. Swift (inset) made the video with her brother, Austin, Broadway star Todrick Hall, and model friends Lily Donaldson, Leah McCarthy, and Martha Hunt. The “mannequin challenge’’ continues to be all the rage on social media these days. For the uninitiated, it involves shooting a video of people standing still in different poses; when the person holding the camera continously moves around them, it creates a cool visual effect. Other celebrities who have taken the “mannequin challenge’’ recently include Adele, Blac Chyna, Britney Spears, Ellen DeGeneres, Paul McCartney, and Kevin Heart.