[Reminder] Broaden with textfield and unlimited message for customized end_membership

preferences/migrations/0060_auto_20190712_1821.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2019-07-12 16:21
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('preferences', '0059_auto_20190120_1739'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='reminder',
+            name='message',
+            field=models.TextField(blank=True, default='', help_text='Message displayed specifically for this reminder', null=True),
+        ),
+    ]

preferences/models.py

@@ -380,8 +380,7 @@ class Reminder(AclMixin, models.Model):
         unique=True,
         help_text=_("Delay between the email and the membership's end")
     )
-    message = models.CharField(
+    message = models.TextField(
-        max_length=255,
         default="",
         null=True,
         blank=True,