Fix bug in /city/state/:id route

Missing .toParam() method in squel

src/libs/routes/city.js

@@ -29,7 +29,7 @@ cityApp.get('/ibge/:id', (req, res, next) => {
 
 cityApp.get('/state/:id', (req, res, next) => {
     req.sql = squel.select().from('municipios').where('fk_estado_id = ?',
-        parseInt(req.params.id, 10));
+        parseInt(req.params.id, 10)).toParam();
     next();
 }, query, response('city'));