Rename posted_on column to created_on

db/newsgroup.sql

@@ -2,7 +2,7 @@ begin transaction;
 
 create table newsgroup_message (
     id         INTEGER PRIMARY KEY NOT NULL,
-    posted_on DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    created_on DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
     sender     TEXT NOT NULL,
     subject    TEXT NOT NULL,
     content    TEXT NOT NULL

lib/nntp/tiny/db.py

@@ -12,7 +12,7 @@ class Database():
         sql = """
             insert into
                 newsgroup_message
-            (posted_on, sender, subject, content) values (?, ?, ?, ?)
+            (created_on, sender, subject, content) values (?, ?, ?, ?)
         """
 
         self.db.execute(sql, (