Why doesn't it show an error in the browser?

Question

Ruby on Rails

Updated to rails 4.2.
Stopped displaying an error in the browser.
Now we need to look at it in the log. Why?
Now like this.

Answer 1

Understood. It's the gem 'web-console'. If you remove it, then everything will be fine.
And it works with better_erros web-console))

Answer 2

It looks like it was launched in a production environment
Or just config.assets.raise_runtime_errors is not true, or config.consider_all_requests_local in environment/development.rb