fix(create): last object when auto-increment key

Fix the criteria passed to the `findOne()` when getting the last object if the schema has an auto-increment PK. The result of the previous query is an array containing the desired object, but prior to this commit we were looking for the `seq` property on the array, not the inner object.

src/helpers.js

@@ -113,7 +113,7 @@ export function findLastObject (model, object) {
     : model.ctx.knex(model.name).first().where({ [key]: object[key] })
 
   return runQuery(model.ctx, query, true)
-    .then(res => hasIncrements ? model.findOne({ [key]: res.seq }) : res)
+    .then(res => hasIncrements ? model.findOne({ [key]: res[0].seq }) : res)
 }
 
 function findKey (schema) {