Fix/sorted section list 467 (#790)

* Sort section list by its abbreviation

* Changed RegistrationForm to CustomUserCreationForm
This is the same form that admin page uses when creating users.
RegistrationForm is not affected by change in forms.py in commit:
9be07d3
and thereby did not get a sorted section list from previous change.
I do not see the diffrence in accont creation between the two forms.

* Changed forms.py
Changed so that section sorting occurs on all ModelForm's.
This allows us to yet again use a custom ModelForm for admin page
and another for the registration page.

src/members/forms.py

@@ -24,6 +24,11 @@
 
 
 class MemberForm(forms.ModelForm):
+    section = forms.ModelChoiceField(
+        required=False,
+        queryset=Section.objects.order_by('abbreviation'),
+        label=_('Section'),
+    )
     person_number = PersonNumberField(
         label=_('Person number'),
         help_text=_('Person number using the YYYYMMDD-XXXX format.'),
@@ -81,6 +86,12 @@ def save(self, commit=True):
 
 
 class RegistrationForm(MemberForm, auth.UserCreationForm):
+    section = forms.ModelChoiceField(
+        required=False,
+        queryset=Section.objects.order_by('abbreviation'),
+        label=_('Section'),
+    )
+
     class Meta:
         model = Member
         fields = ['username', 'email', 'phone_number', 'section']
@@ -216,6 +227,12 @@ def password_enabled(self):
         widget=forms.PasswordInput,
         help_text=_("Enter the same password as above, for verification."))
 
+    section = forms.ModelChoiceField(
+        required=False,
+        queryset=Section.objects.order_by('abbreviation'),
+        label=_('Section'),
+    )
+
     is_superuser = forms.BooleanField(
         label=_("Administrator"), required=False,
         help_text=_('Administrators have full access to manage any object '
@@ -304,6 +321,11 @@ def save(self, commit=True):
 
 class UserEditForm(UserForm):
     password_required = False
+    section = forms.ModelChoiceField(
+        required=False,
+        queryset=Section.objects.order_by('abbreviation'),
+        label=_('Section'),
+    )
 
     def __init__(self, *args, **kwargs):
         kwargs.pop('editing_self', False)
@@ -348,7 +370,7 @@ class CustomUserEditForm(UserEditForm):
     )
     section = forms.ModelChoiceField(
         required=False,
-        queryset=Section.objects,
+        queryset=Section.objects.order_by('abbreviation'),
         label=_('Section'),
     )
     status = forms.ChoiceField(
@@ -412,7 +434,7 @@ class CustomUserCreationForm(UserCreationForm):
     )
     section = forms.ModelChoiceField(
         required=False,
-        queryset=Section.objects,
+        queryset=Section.objects.order_by('abbreviation'),
         label=_("Section"),
     )