do not use `NOT NULL` with `DEFAULT` at the same time

isso/db/comments.py

@@ -34,9 +34,9 @@ class Comments:
             '    created FLOAT NOT NULL, modified FLOAT, mode INTEGER, remote_addr VARCHAR,',
             '    text VARCHAR, author VARCHAR, email VARCHAR, website VARCHAR,',
             '    likes INTEGER DEFAULT 0, dislikes INTEGER DEFAULT 0, voters BLOB NOT NULL,',
-            '    notification INTEGER NOT NULL DEFAULT 0);'])
+            '    notification INTEGER DEFAULT 0);'])
         try:
-            self.db.execute(['ALTER TABLE comments ADD COLUMN notification INTEGER NOT NULL DEFAULT 0;'])
+            self.db.execute(['ALTER TABLE comments ADD COLUMN notification INTEGER DEFAULT 0;'])
         except:
             pass