Add a file upload type to questions (#534)

* Initial stuff

* More features

src/pretix/base/migrations/0064_auto_20170703_0912.py

@@ -0,0 +1,27 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.2 on 2017-07-03 09:12
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+import pretix.base.models.orders
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0063_auto_20170702_1711'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='questionanswer',
+            name='file',
+            field=models.FileField(blank=True, null=True, upload_to=pretix.base.models.orders.answerfile_name),
+        ),
+        migrations.AlterField(
+            model_name='question',
+            name='type',
+            field=models.CharField(choices=[('N', 'Number'), ('S', 'Text (one line)'), ('T', 'Multiline text'), ('B', 'Yes/No'), ('C', 'Choose one from a list'), ('M', 'Choose multiple from a list'), ('F', 'File upload')], max_length=5, verbose_name='Question type'),
+        ),
+    ]