Take a look at these apps. They have an option for a contact (door) sensor built in. When open it turns off the thermostat and when closed it resumes normal operation.
[RELEASE] Mode Based Thermostat - Control Multiple Thermostats Temperature / Remote Temperature Sensors when Changing Modes
[RELEASE] 5-2 Day Programmable Thermostat Scheduler (Weekday, Weekend) with Remote Temperature Sensor for each Schedule