set up model relationship user -- job
fixing model user--job
Merge branch 'create_case_model' of https://github.com/KaFaiC/tutorhub into KaFaiC-create_case_model

Conflicts:
	db/schema.rb
Merge branch 'KaFaiC-create_case_model'
fix schema
Merge branch 'user-job-relationship'
Change jobs belong to Tutor instead of belonging to Student