Make source label field unique.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/sources/migrations/0019_auto_20180803_0440.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.11 on 2018-08-03 04:40
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sources', '0018_auto_20180608_0057'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='source',
+            name='label',
+            field=models.CharField(db_index=True, max_length=64, unique=True, verbose_name='Label'),
+        ),
+    ]

mayan/apps/sources/models.py

@@ -51,7 +51,9 @@ logger = logging.getLogger(__name__)
 
 @python_2_unicode_compatible
 class Source(models.Model):
-    label = models.CharField(max_length=64, verbose_name=_('Label'))
+    label = models.CharField(
+        db_index=True, max_length=64, unique=True, verbose_name=_('Label')
+    )
     enabled = models.BooleanField(default=True, verbose_name=_('Enabled'))
 
     objects = InheritanceManager()