there are command-line options which you can add to bash scripts, can be added in the header like #!/bin/bash -e

set -x is very useful while writing shell scripts. It echos commands being run (even in for loops) which helps in debugging. Put this at the top of script file, and see the magic!

You can scope relations like has_many, has_one and belongs_to. Eg: has_one :policy, -> { where active: true }

We can make use of ActiveRecord's unscoped method to accept a blocks, such that we can obtain associations bypassing the default scope on the associations.

We can make use of Set instead of an Array in Ruby when we would like to create sequences without duplicates and also can be used to compare two sets disregarding order as compared to array for which order of elements matter.