Add user tripcodes

Users can separate their name and a password with ## to create the
illusion of consistent posting.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

board/migrations/0002_post_tripcode.py

@@ -0,0 +1,18 @@
+# Generated by Django 4.1b1 on 2022-07-20 05:50
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("board", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="post",
+            name="tripcode",
+            field=models.CharField(blank=True, max_length=10),
+        ),
+    ]