Made sales log completely read-only; made user-account association read-only

cash/admin.py

@@ -30,7 +30,7 @@ class AccountForm(forms.ModelForm):
 class AccountAdmin(admin.ModelAdmin):
 	list_display = ('user', 'card_number', 'credit', 'transaction_link')
 	form = AccountForm
-	readonly_fields = ('credit',)
+	readonly_fields = ('user', 'credit',)
 	fieldsets = (
 	    (None, {
 	        'fields': ('user', 'card_number', 'credit'),
@@ -101,6 +101,8 @@ class ProductCategoryAdmin(admin.ModelAdmin):
 class SalesLogEntryAdmin(admin.ModelAdmin):
 	list_display = ('account', 'timestamp', 'product', 'count', 'unit_price')
 	list_filter = ['account', 'timestamp', 'product']
+	# Make sales log entries completely read-only
+	readonly_fields = SalesLogEntry._meta.get_all_field_names()
 
 class TransactionAdmin(admin.ModelAdmin):
 	list_display = ('account', 'timestamp', 'subject', 'description', 'amount')