How to create and use SQL view in Rails app

Imagine you have a Rails app using Postgres DB (or other) with 100,1000,10K... active users.Depending on your project, eventually, you can get to the point when you need to add SQL views to your App (what is SQL view)There are multiple reasons to do it:security (you want to hide the content of some tables)simplicity (you can create a more suitable format to work with your data)performance (you can "materialize" data of your views, it can make your app super fast)calculations (you can move some calculations/aggregations into real-time views).