feat: enable access to languages in admin

src/fellchensammlung/admin.py

@@ -1,6 +1,6 @@
 from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
 from django.contrib import admin
-from .models import User
+from .models import User, Language
 
 from .models import Animal, Species, RescueOrganization, AdoptionNotice, Location, Rule, Image, ModerationAction, \
     Report, Member
@@ -31,3 +31,4 @@ admin.site.register(Rule)
 admin.site.register(Image)
 admin.site.register(Report)
 admin.site.register(ModerationAction)
+admin.site.register(Language)