 Shares of Muscle Maker Inc. rose 1.6 in premarket trading Thursday, after the parent of the Muscle Maker Grill fast-casual burger chain said it will start accepting bitcoin as an alternative to cash, credit or debit payments. The company said bitcoin acceptance will start with accepting the cryptocurrency for initial fees for new franchises, then expand to online meal plan subscriptions with its Superfit Foods brand and eventually will expand to everyday food purchases companywide. 