/usr/local/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require': cannot load such file -- redis (LoadError)

This error message indicates that the program is unable to find and load the required Redis library or gem.

To resolve this issue, you can try the following steps:

1. Check if Redis is installed on your system. If not, install it using a package manager or by downloading and compiling the source code.
2. Check if the Redis gem is installed in your Ruby environment. You can check this by running the command `gem list` in your terminal.
3. If the Redis gem is not installed, install it using the command `gem install redis`.
4. If the Redis gem is already installed, try updating it to the latest version using the command `gem update redis`.

If none of the above steps work, you may need to check if there are any issues with your Ruby environment or the program itself.