Add custom css background

judge/migrations/0168_css_background.py

@@ -0,0 +1,24 @@
+# Generated by Django 3.2.18 on 2023-09-02 00:30
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("judge", "0167_ultimate_contest_format"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="profile",
+            name="css_background",
+            field=models.TextField(
+                blank=True,
+                help_text='CSS custom background properties: url("image_url"), color, etc',
+                max_length=300,
+                null=True,
+                verbose_name="Custom background",
+            ),
+        ),
+    ]