Add option to disable bookmark URL validation (#57)

* Add option for disabled bookmark URL validation (#36)

* Add options documentation (#36)

bookmarks/migrations/0005_auto_20210103_1212.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.2.13 on 2021-01-03 12:12
+
+import bookmarks.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('bookmarks', '0004_auto_20200926_1028'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='bookmark',
+            name='url',
+            field=models.CharField(max_length=2048, validators=[bookmarks.validators.BookmarkURLValidator()]),
+        ),
+    ]