Added fields to SiteUser for the user's d.o.b. and gender.  Added a Wieght table that stores a user's weight on the date the Weight object is saved to the database
Changed the date field of Weight so that it must be specifiedi instead of automatically saving the current date
Fixed populate.py to pass pep8
Merge pull request #80 from CSc436/75WeightTable

Added fields to SiteUser for the user's d.o.b. and gender.  Added a Wieg...