rails generate devise install errors

I run a command rails g devise:install but got this error message. I appreciate your help.

/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:244:in rescue in load_dependency': /home/ubuntu/workspace/config/environments/development.rb:44: syntax error, unexpected keyword_end, expecting end-of-input (SyntaxError) from /usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:237:inload_dependency' from /usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in require' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/engine.rb:598:inblock (2 levels) in ' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/engine.rb:597:in each' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/engine.rb:597:inblock in ' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/initializable.rb:30:in instance_exec' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/initializable.rb:30:inrun' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/initializable.rb:55:in block in run_initializers' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:228:inblock in tsort_each' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:350:in block (2 levels) in each_strongly_connected_component' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:422:inblock (2 levels) in each_strongly_connected_component_from' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:431:in each_strongly_connected_component_from' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:421:inblock in each_strongly_connected_component_from' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/initializable.rb:44:in each' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/initializable.rb:44:intsort_each_child' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:415:in call' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:415:ineach_strongly_connected_component_from' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:349:in block in each_strongly_connected_component' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:347:ineach' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:347:in call' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:347:ineach_strongly_connected_component' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:226:in tsort_each' from /usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/tsort.rb:205:intsort_each' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/initializable.rb:54:in run_initializers' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/application.rb:352:ininitialize!' from /home/ubuntu/workspace/config/environment.rb:5:in <top (required)>' from /usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:inrequire' from /usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in block in require' from /usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:240:inload_dependency' from /usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:274:in require' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/application.rb:328:inrequire_environment!' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:142:in require_application_and_environment!' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:128:ingenerate_or_destroy' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:50:in generate' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands/commands_tasks.rb:39:inrun_command!' from /usr/local/rvm/gems/ruby-2.3.0/gems/railties-4.2.5/lib/rails/commands.rb:17:in <top (required)>' from bin/rails:9:inrequire' from bin/rails:9:in `'