First functioning commit

TODO

- [ ] Delay task (Celery?)
- [ ] Store the image in a subfolder unique to the edition, to make cleaning up the image easy
- [ ] Clean up the image before replacing it
- [ ] Ensure that the image will be cleaned when the edition is deleted ??
- [ ] Use instance custom colors?
- [ ] Use book cover color base?

bookwyrm/migrations/0076_book_preview_image.py

@@ -0,0 +1,21 @@
+# Generated by Django 3.2 on 2021-05-24 18:03
+
+import bookwyrm.models.fields
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("bookwyrm", "0075_announcement"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="edition",
+            name="preview_image",
+            field=bookwyrm.models.fields.ImageField(
+                blank=True, null=True, upload_to="previews/"
+            ),
+        ),
+    ]