Support for MySQL functions?

Hey,

I'd like to use MySQL functions like MBRContains() and GeomFromText(), is there a way to do that?

Right now I'd like to set the `location` property of my model instance to `GeomFromText("LINESTRING(0 0, 1 1)", 4055)`, but (of course) the mysql adapter escapes it.

For querying, you could introduce a `conditions` property for the .all() function that takes a string and a splash of arguments that will be escaped and placed into the question marks inside the string. Just like rails does it.

Look at the MySQL adapter's escaping logic, likely in lib/adapters/mysql.js or similar. The user wants to pass raw SQL functions like GeomFromText for model properties and use a conditions property for .all() queries. Start by examining how property values are currently escaped and how query conditions are built. Check if there's existing support for raw SQL fragments. 'Done' means the adapter can accept and not escape specific MySQL functions for both data assignment and query conditions.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.