I am using Ruby 2.4.2. When I run bundle install, it shows the following error:
Your Ruby version is 2.4.1, but your Gemfile specified 2.3.3
It showing this error because in your Gemfile you have specified Ruby version '2.3.3'.
You have two options: one is to remove the Ruby version declaration from your Gemfile, the second to specify the version that is installed on the system in Gemfile.
ruby '2.4.1'
It should be like that in your gemfile.
If you want to use Ruby '2.4.2' then install it in your system and specify the same in Gemfile. You can use RVM or rbenv to manage multiple versions of Ruby.