PS C:\Users\user\dropbox\5. 블로그\devYurim.github.io> jekyll build
C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/bundler-1.16.3/lib/bundler/spec_set.rb:91:in `block in materialize': Could not find eventmachine-1.2.7-x64-mingw32 in any of the sources (Bundler::GemNotFound)
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/bundler-1.16.3/lib/bundler/spec_set.rb:85:in `map!'
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/bundler-1.16.3/lib/bundler/spec_set.rb:85:in `materialize'
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/bundler-1.16.3/lib/bundler/definition.rb:171:in `specs'
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/bundler-1.16.3/lib/bundler/definition.rb:238:in `specs_for'
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/bundler-1.16.3/lib/bundler/definition.rb:227:in `requested_specs'
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/bundler-1.16.3/lib/bundler/runtime.rb:108:in `block in definition_method'
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/bundler-1.16.3/lib/bundler/runtime.rb:20:in `setup'
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/bundler-1.16.3/lib/bundler.rb:107:in `setup'
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/jekyll-3.8.0/lib/jekyll/plugin_manager.rb:50:in `require_from_bundler'
        from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/jekyll-3.8.0/exe/jekyll:11:in `<top (required)>'
        from C:/Ruby24-x64/bin/jekyll:23:in `load'
        from C:/Ruby24-x64/bin/jekyll:23:in `<main>'

$ bundle exec jekyll serve

Could not find eventmachine-1.2.7-x64-mingw32 in any of the sources
Run `bundle install` to install missing gems.
PS C:\Users\user\dropbox\5. 블로그\devYurim.github.io> bundle install
Fetching gem metadata from https://rubygems.org/.............
Using rake 10.5.0
Using public_suffix 3.0.2
Using addressable 2.5.2
.....
Using jekyll-category-pages 1.0.0
Using jekyll-theme-type 1.1 from source at `.`
Bundle complete! 3 Gemfile dependencies, 30 gems now installed.
Use `bundle info [gemname]` to see where a bundled gem is installed.
Post-install message from sass:

Ruby Sass is deprecated and will be unmaintained as of 26 March 2019.

* If you use Sass as a command-line tool, we recommend using Dart Sass, the new
  primary implementation: https://sass-lang.com/install

* If you use Sass as a plug-in for a Ruby web framework, we recommend using the
  sassc gem: https://github.com/sass/sassc-ruby#readme

* For more details, please refer to the Sass blog:
  http://sass.logdown.com/posts/7081811