grey@x60:~$ gem install jekyll
Successfully installed jekyll-2.4.0
Parsing documentation for jekyll-2.4.0
Done installing documentation for jekyll after 4 seconds
1 gem installed
grey@x60:~$ jekyll new lifelog
/home/grey/.rvm/gems/ruby-2.1.2/gems/execjs-2.2.1/lib/execjs/runtimes.rb:51:in `autodetect': Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/execjs-2.2.1/lib/execjs.rb:5:in `<module:ExecJS>'
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/execjs-2.2.1/lib/execjs.rb:4:in `<top (required)>'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/coffee-script-2.3.0/lib/coffee_script.rb:1:in `<top (required)>'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/coffee-script-2.3.0/lib/coffee-script.rb:1:in `<top (required)>'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/jekyll-coffeescript-1.0.1/lib/jekyll-coffeescript.rb:2:in `<top (required)>'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/jekyll-2.4.0/lib/jekyll/deprecator.rb:46:in `block in gracefully_require'
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/jekyll-2.4.0/lib/jekyll/deprecator.rb:44:in `each'
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/jekyll-2.4.0/lib/jekyll/deprecator.rb:44:in `gracefully_require'
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/jekyll-2.4.0/lib/jekyll.rb:141:in `<top (required)>'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /home/grey/.rvm/gems/ruby-2.1.2/gems/jekyll-2.4.0/bin/jekyll:6:in `<top (required)>'
	from /home/grey/.rvm/gems/ruby-2.1.2/bin/jekyll:23:in `load'
	from /home/grey/.rvm/gems/ruby-2.1.2/bin/jekyll:23:in `<main>'
	from /home/grey/.rvm/gems/ruby-2.1.2/bin/ruby_executable_hooks:15:in `eval'
	from /home/grey/.rvm/gems/ruby-2.1.2/bin/ruby_executable_hooks:15:in `<main>'