rails db:setup fails with syntax error

I am trying to setup dev.to code on my redhat 8.2. New to web development.

Followed https://docs.dev.to/installation/linux/ to setup dev.to code on my linux box. But, I ended up with below error.

[dev2@localhost dev.to]$ rails db:setup
rails aborted!
SyntaxError: /home/dev2/workarea/src/dev.to/app/liquid_tags/spotify_tag.rb:40: syntax error, unexpected ']'
...rsed_uri.string.split(":")[1..].unshift("https://open.spotif...

What could be the reason?

Thanks in advance.