我正在关注"在Heroku上使用Ruby入门",但在尝试使用本地运行演示应用程序时
$ bundle exec rake db:create db:migrate
我明白了
sam@samoliver:~/ruby-getting-started$ bundle exec rake db:create db:migrate --trace
rake aborted!
Bundler::GemRequireError: There was an error while trying to load the gem 'uglifier'.
/home/sam/.rvm/gems/ruby-2.2.3/gems/bundler-1.11.0/lib/bundler/runtime.rb:80:in `rescue in block (2 levels) in require'
/home/sam/.rvm/gems/ruby-2.2.3/gems/bundler-1.11.0/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
/home/sam/.rvm/gems/ruby-2.2.3/gems/bundler-1.11.0/lib/bundler/runtime.rb:72:in `each'
/home/sam/.rvm/gems/ruby-2.2.3/gems/bundler-1.11.0/lib/bundler/runtime.rb:72:in `block in require'
/home/sam/.rvm/gems/ruby-2.2.3/gems/bundler-1.11.0/lib/bundler/runtime.rb:61:in `each'
/home/sam/.rvm/gems/ruby-2.2.3/gems/bundler-1.11.0/lib/bundler/runtime.rb:61:in `require'
/home/sam/.rvm/gems/ruby-2.2.3/gems/bundler-1.11.0/lib/bundler.rb:99:in `require'
/home/sam/ruby-getting-started/config/application.rb:7:in `<top (required)>'
/home/sam/ruby-getting-started/Rakefile:4:in `require'
/home/sam/ruby-getting-started/Rakefile:4:in `<top (required)>'
/home/sam/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/rake/rake_module.rb:28:in `load'
/home/sam/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/rake/rake_module.rb:28:in `load_rakefile'
/home/sam/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/rake/application.rb:689:in `raw_load_rakefile'
/home/sam/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/rake/application.rb:94:in `block in load_rakefile'
/home/sam/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/rake/application.rb:176:in `standard_exception_handling'
/home/sam/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/rake/application.rb:93:in `load_rakefile'
/home/sam/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/rake/application.rb:77:in `block in …