old_contents: from django.contrib.auth.models import User, Permission, Group
  from opensubmit.models import Course, Grading, GradingScheme, Assignment, SubmissionFile, Submission, TestMachine
  from django.contrib.admin.sites import AdminSite
  
  from user import UserAdmin
  from course import CourseAdmin
  from grading import GradingAdmin
  from gradingscheme import GradingSchemeAdmin
  from assignment import AssignmentAdmin
  from submissionfile import SubmissionFileAdmin
  from submission import SubmissionAdmin
  
  class AdminBackend(AdminSite):
  	site_header = "Administrator Backend"
  	pass
  
  admin_backend = AdminBackend(name="admin")
  admin_backend.register(User, UserAdmin)
  admin_backend.register(Course, CourseAdmin)
  admin_backend.register(TestMachine)
  admin_backend.register(Permission)
  admin_backend.register(Group)
  
  
  class TeacherBackend(AdminSite):
  	site_header = "Teacher Backend"
  	pass
  
  teacher_backend = TeacherBackend(name="teacher")
  teacher_backend.register(Grading, GradingAdmin)
  teacher_backend.register(GradingScheme, GradingSchemeAdmin)
  teacher_backend.register(Assignment, AssignmentAdmin)
  teacher_backend.register(SubmissionFile, SubmissionFileAdmin)
  teacher_backend.register(Submission, SubmissionAdmin)
  teacher_backend.register(Course, CourseAdmin)
  teacher_backend.register(TestMachine)
  
new_contents: from django.contrib.auth.models import User, Permission, Group
  from opensubmit.models import Course, Grading, GradingScheme, Assignment, SubmissionFile, Submission, TestMachine
  from opensubmit import settings
  from django.contrib.admin.sites import AdminSite
  
  from user import UserAdmin
  from course import CourseAdmin
  from grading import GradingAdmin
  from gradingscheme import GradingSchemeAdmin
  from assignment import AssignmentAdmin
  from submissionfile import SubmissionFileAdmin
  from submission import SubmissionAdmin
  
  class AdminBackend(AdminSite):
  	site_header = "Administrator Backend"
  	site_url = settings.MAIN_URL
  	pass
  
  admin_backend = AdminBackend(name="admin")
  admin_backend.register(User, UserAdmin)
  admin_backend.register(Course, CourseAdmin)
  admin_backend.register(TestMachine)
  admin_backend.register(Permission)
  admin_backend.register(Group)
  
  
  class TeacherBackend(AdminSite):
  	site_header = "Teacher Backend"
  	site_url = settings.MAIN_URL
  	pass
  
  teacher_backend = TeacherBackend(name="teacher")
  teacher_backend.register(Grading, GradingAdmin)
  teacher_backend.register(GradingScheme, GradingSchemeAdmin)
  teacher_backend.register(Assignment, AssignmentAdmin)
  teacher_backend.register(SubmissionFile, SubmissionFileAdmin)
  teacher_backend.register(Submission, SubmissionAdmin)
  teacher_backend.register(Course, CourseAdmin)
  teacher_backend.register(TestMachine)
  
subject: Fix 'View Site' link, closes #127