Extension:CentralNotice/cn template mixins table

tmxn_id
Primary key.

Schema summary
mysql> describe cn_template_mixins; +++--+-+-++ +++--+-+-++ +++--+-+-++
 * Field     | Type           | Null | Key | Default | Extra          |
 * tmxn_id   | int(11)        | NO   | PRI | NULL    | auto_increment |
 * tmp_id    | int(11)        | NO   | MUL | NULL    |                |
 * page_id   | int(11)        | NO   | MUL | NULL    |                |
 * mixin_name | varbinary(255) | NO  | MUL | NULL    |                |