school: minimal admin

school/admin.py

+from django.contrib import messages
+from django.core.exceptions import ValidationError
+from django import contrib
+from django.utils.translation import ugettext_lazy as _
+from school import models
+import string
+
+class GroupInline(contrib.admin.TabularInline):
+    model = models.Group
+    extra = 2
+
+class CourseAdmin(contrib.admin.ModelAdmin):
+    model=models.Course
+    inlines = (GroupInline, )
+    filter_horizontal = ('owners', )
+
+class GroupAdmin(contrib.admin.ModelAdmin):
+    model = models.Group
+    filter_horizontal = ('owners', 'members', )
+
+class SemesterAdmin(contrib.admin.ModelAdmin):
+    model=models.Semester
+
+contrib.admin.site.register(models.Course, CourseAdmin)
+contrib.admin.site.register(models.Semester, SemesterAdmin)
+contrib.admin.site.register(models.Group, GroupAdmin)
+