My Family + Thanksgiving = Horror Story for Me?

So, tomorrow is Thanksgiving, a day where you are supposed to meditate on all your blessings and how good life is, in general. All of my family is gathering at my house tomorrow, it being the most commodious out of all our homes. The only problem is, I really do not get along with some of my family members, namely my grandmother. I pride myself on being a tolerant person but my grandmother has an animosity towards me that I find disheartening. My mother and I lived with her in her apartment for a number of years, and those years were the worst of my life. She physically beat me and burnt me, belittled my every move, even though I showed only the utmost respect for her. She still constantly harps about everything I do, and she is a tiresome and embittered old woman. I try to be fair, but I am afraid that I will lose my patience. I really do not want to attend Thanksgiving dinner with her present, it's going to be very miserable. What should I do?