refactor: Use integer choice for search

src/fellchensammlung/forms.py

@@ -1,7 +1,7 @@
 from django import forms
 
 from .models import AdoptionNotice, Animal, Image, ReportAdoptionNotice, ReportComment, ModerationAction, User, Species, \
-    Comment, SexChoicesWithAll
+    Comment, SexChoicesWithAll, DistanceChoices
 from django_registration.forms import RegistrationForm
 from crispy_forms.helper import FormHelper
 from crispy_forms.layout import Submit, Layout, Fieldset, HTML, Row, Column, Field, Hidden
@@ -181,12 +181,8 @@ class CustomRegistrationForm(RegistrationForm):
         self.helper.add_input(Submit('submit', _('Registrieren'), css_class="btn"))
 
 
-def _get_distances():
-    return {i: i for i in [20, 50, 100, 200, 500]}
-
-
 class AdoptionNoticeSearchForm(forms.Form):
     location = forms.CharField(max_length=20, label=_("Stadt"), required=False)
-    max_distance = forms.ChoiceField(choices=_get_distances, label=_("Max. Distanz"))
+    max_distance = forms.ChoiceField(choices=DistanceChoices, initial=DistanceChoices.ONE_HUNDRED, label=_("Suchradius"))
     sex = forms.ChoiceField(choices=SexChoicesWithAll, label=_("Geschlecht"), required=False,
                             initial=SexChoicesWithAll.ALL)

src/fellchensammlung/models.py

@@ -539,6 +539,13 @@ class Animal(models.Model):
         """Returns the url to access a detailed page for the animal."""
         return reverse('animal-detail', args=[str(self.id)])
 
+class DistanceChoices(models.IntegerChoices):
+    TWENTY = 20, '20 km'
+    FIFTY = 50, '50 km'
+    ONE_HUNDRED = 100, '100 km'
+    TWO_HUNDRED = 200, '200 km'
+    FIVE_HUNDRED = 500, '500 km'
+
 
 class Rule(models.Model):
     """