CHANGE: New user signups now require admin approval

Given that I intend to reveal much more data to new users this seems necessary...

RIGS/migrations/0036_profile_is_approved.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.0.13 on 2020-01-10 14:52
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('RIGS', '0035_auto_20191124_1319'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='profile',
+            name='is_approved',
+            # Approve existing profiles automatically, new ones default false. 
+            field=models.BooleanField(default=True),
+        ),
+    ]