I´ve a problem when run Rails server. I just installed gem server, but still not working. I am new to the world of programming . I am grateful to anyone who can help me.
Copy an image of the error: https://i.stack.imgur.com/wS7oS.png.
/home/hugo/.rvm/gems/ruby-2.2.2/gems/activesupport-4.0.5/lib/active_support/values/time_zone.rb:283: warning: circular argument reference - now
/home/hugo/.rvm/gems/ruby-2.2.2/gems/execjs-2.5.2/lib/execjs/runtimes.rb:48:in `autodetect': Could not find a JavaScript runtime. See https://github.com/rails/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/execjs-2.5.2/lib/execjs.rb:5:in `<module:ExecJS>'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/execjs-2.5.2/lib/execjs.rb:4:in `<top (required)>'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/uglifier-2.7.1/lib/uglifier.rb:3:in `require'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/uglifier-2.7.1/lib/uglifier.rb:3:in `<top (required)>'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.2/lib/bundler/runtime.rb:76:in `require'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.2/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.2/lib/bundler/runtime.rb:72:in `each'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.2/lib/bundler/runtime.rb:72:in `block in require'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.2/lib/bundler/runtime.rb:61:in `each'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.2/lib/bundler/runtime.rb:61:in `require'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.2/lib/bundler.rb:133:in `require'
from /home/hugo/pin_board/config/application.rb:7:in `<top (required)>'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/railties-4.0.5/lib/rails/commands.rb:74:in `require'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/railties-4.0.5/lib/rails/commands.rb:74:in `block in <top (required)>'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/railties-4.0.5/lib/rails/commands.rb:71:in `tap'
from /home/hugo/.rvm/gems/ruby-2.2.2/gems/railties-4.0.5/lib/rails/commands.rb:71:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'