1. parsed the value of request param in getStation callback
2. match condition is changed to from_station_id in the methods(getBirthYearsOfThisStation, getGenderPercentageOfThisStation, getUserTypePercentageOfThisStation)
3. Implemented callback for the method, getAverageTimeOfTripsOfThisStation
4. Changed type for tripduration to 'Number' in models.js and created a tripdurationConversion.js file