Add flour, yeast and salt to a mixing bowl and stir to combine. In a cup or small bowl, mix together the water, 1 Tbsp. of olive oil and the apple cider vinegar, then stir into the flour mixture. Mix well; the dough will be sticky. Scrape the dough into the slow cooker and spread out in an even layer. With the slow cooker still turned off, put the lid on and let the dough rise for 30 minutes.