Work around limitation that model forms can only have editable fields.

biscuit/apps/alsijil/forms.py

@@ -10,5 +10,18 @@ class LessonDocumentationForm(forms.ModelForm):
         fields = ['topic', 'homework']
 
 
+class PersonalNoteForm(forms.ModelForm):
+    class Meta:
+        model = PersonalNote
+        fields = ['person', 'absent', 'late', 'excused', 'remarks']
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*awrgs, **kwargs)
+        self.fields['person'].widget.attrs['readonly'] = True
+
+    def clean_person(self):
+      return self.instance.person
+
+
 PersonalNoteFormSet = forms.modelformset_factory(
-    PersonalNote, fields=('person', 'absent', 'late', 'excused', 'remarks'))
+    PersonalNote, form=PersonalNoteForm)

biscuit/apps/alsijil/models.py

@@ -5,7 +5,7 @@ from biscuit.core.mixins import SchoolRelated
 
 
 class PersonalNote(SchoolRelated):
-    person = models.ForeignKey('core.Person', models.CASCADE, editable=False)
+    person = models.ForeignKey('core.Person', models.CASCADE)
 
     week = models.IntegerField()
     lesson_period = models.ForeignKey('chronos.LessonPeriod', models.CASCADE)