Fix null=True vs blank=True on string fields

Django documentation suggests no using null=True, but
instead defaulting to the empty string.  It's
necessary of course to allow blank=True so that
users don't have to enter the field

flangr/posts/migrations/0003_alter_post_body_alter_post_title.py

@@ -0,0 +1,23 @@
+# Generated by Django 4.0.5 on 2022-07-08 20:49
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("posts", "0002_alter_comment_post_alter_post_img"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="post",
+            name="body",
+            field=models.TextField(blank=True, default=""),
+        ),
+        migrations.AlterField(
+            model_name="post",
+            name="title",
+            field=models.CharField(blank=True, default="", max_length=255),
+        ),
+    ]

flangr/posts/models.py

@@ -17,8 +17,8 @@ class Post(models.Model):
     posted = models.DateTimeField(auto_now_add=True)
     public = models.BooleanField(default=False)
 
-    title = models.CharField(max_length=255, null=True)
+    title = models.CharField(max_length=255, blank=True, default="")
-    body = models.TextField(null=True)
+    body = models.TextField(blank=True, default="")
 
     user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)