Add missing migrations.

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

mayan/apps/document_signatures/migrations/0007_auto_20180403_0702.py

@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.11 on 2018-04-03 07:02
+from __future__ import unicode_literals
+
+import django.core.files.storage
+from django.db import migrations, models
+import document_signatures.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('document_signatures', '0006_auto_20160326_0616'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='detachedsignature',
+            name='signature_file',
+            field=models.FileField(blank=True, null=True, storage=django.core.files.storage.FileSystemStorage(location=b'mayan/media/document_storage'), upload_to=document_signatures.models.upload_to, verbose_name='Signature file'),
+        ),
+    ]