Sort ModelAdmin FK fields alphabetically

for the for Component, Product and Version fields.
Fixes kiwitcms#633

tcms/management/admin.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 
 from django.contrib import admin
+from django.contrib.auth import get_user_model
 
 from tcms.management.models import Classification
 from tcms.management.models import Component, Version
@@ -19,6 +20,12 @@ class ProductsAdmin(admin.ModelAdmin):
     list_display = ('id', 'name', 'classification', 'description')
     list_filter = ('id', 'name', 'classification')
 
+    def formfield_for_foreignkey(self, db_field, request, **kwargs):
+        if db_field.name == "classification":
+            kwargs["queryset"] = Classification.objects.order_by('name')
+
+        return super().formfield_for_foreignkey(db_field, request, **kwargs)
+
 
 class PriorityAdmin(admin.ModelAdmin):
     search_fields = ('value', 'id')
@@ -34,12 +41,27 @@ class ComponentAdmin(admin.ModelAdmin):
     def get_queryset(self, request):
         return super().get_queryset(request).select_related('product', 'initial_owner')
 
+    def formfield_for_foreignkey(self, db_field, request, **kwargs):
+        if db_field.name == "product":
+            kwargs["queryset"] = Product.objects.order_by('name')
+
+        if db_field.name == "initial_owner" or db_field.name == "initial_qa_contact":
+            kwargs["queryset"] = get_user_model().objects.order_by('username')
+
+        return super().formfield_for_foreignkey(db_field, request, **kwargs)
+
 
 class VersionAdmin(admin.ModelAdmin):
     search_fields = ('value', 'id')
     list_display = ('id', 'product', 'value')
     list_filter = ('product',)
 
+    def formfield_for_foreignkey(self, db_field, request, **kwargs):
+        if db_field.name == "product":
+            kwargs["queryset"] = Product.objects.order_by('name')
+
+        return super().formfield_for_foreignkey(db_field, request, **kwargs)
+
 
 class BuildAdmin(admin.ModelAdmin):
     search_fields = ('name', 'build_id')