title: Unable to run rails server: `require': cannot load such file -- net/ssh (LoadError)
body: <p>I am trying to learn ruby on rails using the michael hartl guide. In the past, I was able to get through the setup of a new rails webapp. Now, when I try to run the server, I am getting this error:</p>
  
  <pre><code>/home/ss/.rvm/gems/ruby-2.2.2/gems/fog-1.26.0/lib/fog/joyent/compute.rb:3:in `require': cannot load such file -- net/ssh (LoadError)
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/fog-1.26.0/lib/fog/joyent/compute.rb:3:in `&lt;top (required)&gt;'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/fog-1.26.0/lib/fog/joyent.rb:1:in `require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/fog-1.26.0/lib/fog/joyent.rb:1:in `&lt;top (required)&gt;'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/fog-1.26.0/lib/fog.rb:41:in `require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/fog-1.26.0/lib/fog.rb:41:in `&lt;top (required)&gt;'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/carrierwave-0.10.0/lib/carrierwave/storage/fog.rb:3:in `require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/carrierwave-0.10.0/lib/carrierwave/storage/fog.rb:3:in `&lt;top (required)&gt;'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/carrierwave-0.10.0/lib/carrierwave/storage.rb:9:in `require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/carrierwave-0.10.0/lib/carrierwave/storage.rb:9:in `&lt;top (required)&gt;'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/carrierwave-0.10.0/lib/carrierwave.rb:78:in `require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/carrierwave-0.10.0/lib/carrierwave.rb:78:in `&lt;top (required)&gt;'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.6/lib/bundler/runtime.rb:76:in `require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.6/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.6/lib/bundler/runtime.rb:72:in `each'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.6/lib/bundler/runtime.rb:72:in `block in require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.6/lib/bundler/runtime.rb:61:in `each'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.6/lib/bundler/runtime.rb:61:in `require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/bundler-1.10.6/lib/bundler.rb:134:in `require'
      from /home/ss/workspace/hartl/sample_app/config/application.rb:7:in `&lt;top (required)&gt;'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/railties-4.2.2/lib/rails/commands/commands_tasks.rb:78:in `require'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/railties-4.2.2/lib/rails/commands/commands_tasks.rb:78:in `block in server'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/railties-4.2.2/lib/rails/commands/commands_tasks.rb:75:in `tap'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/railties-4.2.2/lib/rails/commands/commands_tasks.rb:75:in `server'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/railties-4.2.2/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/railties-4.2.2/lib/rails/commands.rb:17:in `&lt;top (required)&gt;'
      from /home/ss/workspace/hartl/sample_app/bin/rails:10:in `require'
      from /home/ss/workspace/hartl/sample_app/bin/rails:10:in `&lt;top (required)&gt;'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/spring-1.1.3/lib/spring/client/rails.rb:27:in `load'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/spring-1.1.3/lib/spring/client/rails.rb:27:in `call'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/spring-1.1.3/lib/spring/client/command.rb:7:in `call'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/spring-1.1.3/lib/spring/client.rb:26:in `run'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/spring-1.1.3/bin/spring:48:in `&lt;top (required)&gt;'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `load'
      from /home/ss/.rvm/gems/ruby-2.2.2/gems/spring-1.1.3/lib/spring/binstub.rb:11:in `&lt;top (required)&gt;'
      from /home/ss/workspace/hartl/sample_app/bin/spring:13:in `require'
      from /home/ss/workspace/hartl/sample_app/bin/spring:13:in `&lt;top (required)&gt;'
      from bin/rails:4:in `load'
      from bin/rails:4:in `&lt;main&gt;'
  </code></pre>