created user model
added validations to user
added index by email to user db
added user show page
added password +validations/confirmations
password authentication
added factory and 'show' tests
updated show page
updated about page
Merge branch 'modeling-users'

Conflicts:
	webrat.log
added studentgroups
layout fix
Merge branch 'modeling-student-groups'

Conflicts:
	webrat.log
added Student model
cleaned some messes, added student and studentgroup models