having problem with -> rails g rspec: install

i am running on ruby 2.3, and using rails 4.2.0 for my project

also rails-rspec ‘~>3.0.0’

when i run $ rails g rspec:install i get this problem. any help please

C:\Sites\livechat>rails g rspec:install
C:/RailsInstaller/Ruby2.3.3/lib/ruby/gems/2.3.0/gems/railties-4.2.0/lib/rails/ra
iltie/configuration.rb:95:in method_missing': undefined method load_defaults’
for #Rails::Application::Configuration:0x47b58e8 (NoMethodError)
from C:/Sites/livechat/config/application.rb:12:in `class:Application

    from C:/Sites/livechat/config/application.rb:10:in `<module:Livechat>'
    from C:/Sites/livechat/config/application.rb:9:in `<top (required)>'
    from C:/RailsInstaller/Ruby2.3.3/lib/ruby/gems/2.3.0/gems/bootsnap-1.3.1

/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in require' from C:/RailsInstaller/Ruby2.3.3/lib/ruby/gems/2.3.0/gems/bootsnap-1.3.1 /lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in block in require
_with_bootsnap_lfi’

Have you run bundle on your app to see which gems are installed? It looks like maybe you’re using a version of bootsnap gem that isn’t playing well with the defaults for the Rails you have loaded.

please can you help with which version of bootsnap is compatible with rails 5.2

please can you help with which version of bootsnap is compatible with rails
5.2

Generate a blank rails app with 5.2 and see what bundler installs.
But I'm not sure how that's relevant to your previously described
problem...