все шло как по маслу а когда захотел запустить сервер дало ошибку!

Bundle complete! 12 Gemfile dependencies, 54 gems now installed.
Use `bundle show [gemname]` to see where a bundled gem is installed.
run bundle exec spring binstub --all
* bin/rake: spring inserted
* bin/rails: spring inserted
kindix@kindix-VirtualBox:~$ cd my_store
kindix@kindix-VirtualBox:~/my_store$ rails s
/home/kindix/.rvm/gems/ruby-2.3.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:80:in `rescue in block (2 levels) in require': There was an error while trying to load the gem 'uglifier'. (Bundler::GemRequireError)
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `each'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `block in require'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `each'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `require'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/bundler-1.11.2/lib/bundler.rb:99:in `require'
from /home/kindix/my_store/config/application.rb:7:in `<top (required)>'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:78:in `require'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:78:in `block in server'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:75:in `tap'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:75:in `server'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5.2/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/railties-4.2.5.2/lib/rails/commands.rb:17:in `<top (required)>'
from /home/kindix/my_store/bin/rails:9:in `require'
from /home/kindix/my_store/bin/rails:9:in `<top (required)>'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/spring-1.6.4/lib/spring/client/rails.rb:28:in `load'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/spring-1.6.4/lib/spring/client/rails.rb:28:in `call'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/spring-1.6.4/lib/spring/client/command.rb:7:in `call'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/spring-1.6.4/lib/spring/client.rb:28:in `run'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/spring-1.6.4/bin/spring:49:in `<top (required)>'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/spring-1.6.4/lib/spring/binstub.rb:11:in `load'
from /home/kindix/.rvm/gems/ruby-2.3.0/gems/spring-1.6.4/lib/spring/binstub.rb:11:in `<top (required)>'
from /home/kindix/my_store/bin/spring:13:in `require'
from /home/kindix/my_store/bin/spring:13:in `<top (required)>'
from bin/rails:3:in `load'
from bin/rails:3:in `<main>'