Extension:Echo/echo push subscription table

mysql> describe echo_push_subscription; +--+-+--+-+---+-+ +--+-+--+-+---+-+ +--+-+--+-+---+-+
 * Field           | Type                | Null | Key | Default           | Extra                       |
 * eps_id          | int(10) unsigned    | NO   | PRI | NULL              | auto_increment              |
 * eps_user        | int(10) unsigned    | NO   | MUL | NULL              |                             |
 * eps_token       | blob                | NO   | MUL | NULL              |                             |
 * eps_token_sha256 | binary(64)         | NO   | UNI | NULL              |                             |
 * eps_provider    | tinyint(3) unsigned | NO   | MUL | NULL              |                             |
 * eps_updated     | timestamp           | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
 * eps_data        | blob                | YES  |     | NULL              |                             |
 * eps_topic       | tinyint(3) unsigned | YES  | MUL | NULL              |                             |