added admin models for Course and Assignment

assignments/admin.py

@@ -3,5 +3,14 @@ from django.contrib import admin
 from .models import Assignment
 from .models import Course
 
-admin.site.register(Assignment)
-admin.site.register(Course)
+
+class AssignmentAdmin(admin.ModelAdmin):
+    readonly_fields = ('id',)
+
+
+class CourseAdmin(admin.ModelAdmin):
+    readonly_fields = ('id',)
+
+
+admin.site.register(Assignment, AssignmentAdmin)
+admin.site.register(Course, CourseAdmin)