Ubuntu, Ruby, Ruby on Rails Installation Problems (Cant visit localhost:3000)

This is my first time learning to code, first time on Linux and first time on stackeroverflow so I dont know if its glaringly obvious where I have gone wrong.

I have followed this guide http://ift.tt/1XFAH6e and everything was working as the guide said until I got to this section:

run bundle install --local /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in require': cannot load such file -- bundler (LoadError) from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:inrequire' from /usr/lib/ruby/vendor_ruby/rails/generators/app_base.rb:328:in bundle_command' from /usr/lib/ruby/vendor_ruby/rails/generators/app_base.rb:344:inrun_bundle' from (eval):1:in run_bundle' from /usr/lib/ruby/vendor_ruby/thor/command.rb:27:inrun' from /usr/lib/ruby/vendor_ruby/thor/invocation.rb:126:in invoke_command' from /usr/lib/ruby/vendor_ruby/thor/invocation.rb:133:inblock in invoke_all' from /usr/lib/ruby/vendor_ruby/thor/invocation.rb:133:in each' from /usr/lib/ruby/vendor_ruby/thor/invocation.rb:133:inmap' from /usr/lib/ruby/vendor_ruby/thor/invocation.rb:133:in invoke_all' from /usr/lib/ruby/vendor_ruby/thor/group.rb:232:indispatch' from /usr/lib/ruby/vendor_ruby/thor/base.rb:440:in start' from /usr/lib/ruby/vendor_ruby/rails/commands/application.rb:17:in' from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in require' from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:inrequire' from /usr/lib/ruby/vendor_ruby/rails/cli.rb:14:in <top (required)>' from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:inrequire' from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in require' from /usr/bin/rails:9:in' tom@Laptop:~$ cd myapp tom@Laptop:~/myapp$ rake db:create rake aborted! LoadError: cannot load such file -- bundler/setup /home/tom/myapp/config/boot.rb:3:in <top (required)>' /home/tom/myapp/config/application.rb:1:in' /home/tom/myapp/Rakefile:4:in <top (required)>' (See full trace by running task with --trace) tom@Laptop:~/myapp$ rails server /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:inrequire': cannot load such file -- bundler/setup (LoadError) from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in require' from /home/tom/myapp/config/boot.rb:3:in' from bin/rails:3:in require_relative' from bin/rails:3:in'

Sorry I don't know how to format this correctly. When I visit localhost:3000 I just get Network error.

Has anyone got any idea how to solve this? Thanks for your time.