Weekly work target

[Danwhy]

As a student, I want to be able to add the amount of time I am available to study/work for the week, so that I can find out the best way to prioritise the time I have available.

Requirements

• Student can enter the amount of time they have available
• This is saved to the database
• And used to calculate targets for the week

[stianr]

His @Danwhy - if possible, could we constrain the amount of time to integer hours - just for neatness.