Add logic to update meal details

[coder-daria]

Till now the user can set his meal preferences (breakfast, dinner, supper etc) at his preferred time and choose the amount of kcal he wants to eat per day. After applying the new logic the user not only will be able to see meal details, but he will also be able to update them (but only meals on the current day, meals from previous days, weeks or years won't be able to be updated).