There is an issue on Yii2 to redirecting / urls to /frontend/web.
In other words we need a way to hidden /frontend/web from addresses.
We will do this without changing Apache configuration and creating virtual host or setting document root (It's good for share hostings that we have not access to apache.conf)
With the adoption of PJax on Yii2 things have change quite a bit with GridView when it comes to work with them in AJAX mode. It will probably be confusing at the beginning, but then you will soon realize how powerful the new approach is.
This article tries to describe the practical techniques of searching by a HAS_MANY relation using ActiveRecord of Yii 2.0.
This is a simple example in Yii2.0 to understand how you can write a custom component and use it inside your app.(basic template)
There are a few issues with the other solutions I originally used that I found from other wikis. I address the issues I had in this much simpler and shorter way. I am also going to explain what is going into way more detail than others to help people understand what's going on.
One of the things you will find tricky to implement is the the sorting and filtering of a GridView's column that displays related model data.