Implement check on lat lon

[agottardo]

Should also be added to the CREATE TABLE syntax we will attach to the submission, so not closing for now.

[agottardo]

@iandelrio remember to add this at the end of the final .sql when submitting:

ALTER TABLE locations ADD CHECK (longitude>=-123.27 AND longitude <= -123.22 AND latitude >= 49.241 AND latitude <= 49.283);

In PHP:

$longitude >= -123.27 && $longitude <= -123.22 && $latitude >= 49.241 && $latitude <= 49.283;