Weird warring on rails server startup

In my application whenever I try to start rails server following warning pop-up

warning: constant ::Fixnum is deprecated
warning: constant ::Bignum is deprecated
=> Booting Puma
=> Rails 5.0.1 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
warning: constant ::Fixnum is deprecated
Puma starting in single mode...
* Version 3.6.2 (ruby 2.4.0-p0), codename: Sleepy Sunday Serenity
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://localhost:3000
Use Ctrl-C to stop

Is it something from backend or I'm missing something to install on my
machine which produce this.

Ruby 2.4 is changing the way it handles integers, at the moment it is harmless but annoying, or you can roll back to use Ruby 2.3.3

You faced this waring because of ruby version 2.4

refer this link :-