Sqlite and ESCAPE
You can put together a clause:

``` python
>>> query = User.select().where(User.username ** Clause('t\_t', SQL("ESCAPE '\\'")))
>>> print query.sql()
('SELECT t1."id", t1."username" FROM "user" AS t1 WHERE (t1."username" LIKE ? ESCAPE \'\\\')', [u't\\_t'])

```

Hi,

I'm trying to use the LIKE operator to match entries containing underscore '_' and percent '%'.
If I understood correctly the Sqlite doc [1], I have to add the ESCAPE 'my escape char'
The common escape char is '\' (I saw '!' too in some online examples)

```
sqlite> SELECT 't_t' LIKE 't\_t' ESCAPE '\';
1
sqlite> SELECT 'tft' LIKE 't\_t' ESCAPE '\';
0
```

Is there a way to register a new operator that add  the ESCAPE clause or override the contains function ?
[1] http://www.sqlite.org/lang_expr.html#like
