Add unique constraint to 'Url' field in threats_watcher

Update model to make the 'Url' field unique to prevent duplicates in the database.

Watcher/Watcher/threats_watcher/migrations/0014_alter_source_url.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.0.2 on 2024-07-24 14:56
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('threats_watcher', '0013_auto_20210517_0956'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='source',
+            name='url',
+            field=models.URLField(max_length=350, unique=True),
+        ),
+    ]