Add missing django-polymorphic migrations

Made necessary by the new version of Django-Polymorphic ?

Ref #13

coin/configuration/migrations/0004_auto_20161015_1837.py

@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('configuration', '0003_configuration_comment'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='configuration',
+            name='polymorphic_ctype',
+            field=models.ForeignKey(related_name='polymorphic_configuration.configuration_set+', editable=False, to='contenttypes.ContentType', null=True),
+        ),
+    ]

coin/members/migrations/0013_auto_20161015_1837.py

@@ -0,0 +1,42 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.core.validators
+import django.contrib.auth.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('members', '0012_member_date_last_call_for_membership_fees_email'),
+    ]
+
+    operations = [
+        migrations.AlterModelManagers(
+            name='member',
+            managers=[
+                ('objects', django.contrib.auth.models.UserManager()),
+            ],
+        ),
+        migrations.AlterField(
+            model_name='member',
+            name='email',
+            field=models.EmailField(unique=True, max_length=254, verbose_name='email address'),
+        ),
+        migrations.AlterField(
+            model_name='member',
+            name='groups',
+            field=models.ManyToManyField(related_query_name='user', related_name='user_set', to='auth.Group', blank=True, help_text='The groups this user belongs to. A user will get all permissions granted to each of their groups.', verbose_name='groups'),
+        ),
+        migrations.AlterField(
+            model_name='member',
+            name='last_login',
+            field=models.DateTimeField(null=True, verbose_name='last login', blank=True),
+        ),
+        migrations.AlterField(
+            model_name='member',
+            name='username',
+            field=models.CharField(error_messages={'unique': 'A user with that username already exists.'}, max_length=30, validators=[django.core.validators.RegexValidator('^[\\w.@+-]+$', 'Enter a valid username. This value may contain only letters, numbers and @/./+/-/_ characters.', 'invalid')], help_text='Required. 30 characters or fewer. Letters, digits and @/./+/-/_ only.', unique=True, verbose_name='username'),
+        ),
+    ]