railsでおこったエラーについて

Question

前提・実現したいこと

Cloud9でコントローラの作成を行いたいです。

発生している問題・エラーメッセージ

rails new でひな形を作成し、rails g controller でコントローラの作成を行おうとしたのですが、以下のエラーが発生し、対策もわからず頭を抱えています。なにが原因なのでしょうか…

/home/ec2-user/.rvm/rubies/ruby-2.5.3/lib/ruby/site_ruby/2.5.0/bundler/rubygems_integration.rb:408:in `block (2 levels) in replace_gem': Error loading the 'sqlite3' Active Record adapter. Missing a gem it depends on? can't activate sqlite3 (~> 1.3.6), already activated sqlite3-1.4.0. Make sure all dependencies are added to Gemfile. (LoadError)
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activerecord-5.2.2/lib/active_record/connection_adapters/sqlite3_adapter.rb:12:in `<main>'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `block in require_with_bootsnap_lfi'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/loaded_features_index.rb:65:in `register'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:20:in `require_with_bootsnap_lfi'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:29:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/dependencies.rb:291:in `block in require'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/dependencies.rb:257:in `load_dependency'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/dependencies.rb:291:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activerecord-5.2.2/lib/active_record/connection_adapters/connection_specification.rb:191:in `spec'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activerecord-5.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:952:in `establish_connection'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activerecord-5.2.2/lib/active_record/connection_handling.rb:60:in `establish_connection'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activerecord-5.2.2/lib/active_record/railtie.rb:136:in `block (2 levels) in <class:Railtie>'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/lazy_load_hooks.rb:71:in `instance_eval'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/lazy_load_hooks.rb:71:in `block in execute_hook'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/lazy_load_hooks.rb:62:in `with_execution_control'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/lazy_load_hooks.rb:67:in `execute_hook'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/lazy_load_hooks.rb:52:in `block in run_load_hooks'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/lazy_load_hooks.rb:51:in `each'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/lazy_load_hooks.rb:51:in `run_load_hooks'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activerecord-5.2.2/lib/active_record/base.rb:328:in `<module:ActiveRecord>'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activerecord-5.2.2/lib/active_record/base.rb:27:in `<main>'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `block in require_with_bootsnap_lfi'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/loaded_features_index.rb:65:in `register'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:20:in `require_with_bootsnap_lfi'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/bootsnap-1.3.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:29:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/dependencies.rb:291:in `block in require'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/dependencies.rb:257:in `load_dependency'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/activesupport-5.2.2/lib/active_support/dependencies.rb:291:in `require'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/spring-2.0.2/lib/spring/application.rb:356:in `active_record_configured?'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/spring-2.0.2/lib/spring/application.rb:273:in `disconnect_database'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/spring-2.0.2/lib/spring/application.rb:107:in `preload'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/spring-2.0.2/lib/spring/application.rb:153:in `serve'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/spring-2.0.2/lib/spring/application.rb:141:in `block in run'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/spring-2.0.2/lib/spring/application.rb:135:in `loop'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/spring-2.0.2/lib/spring/application.rb:135:in `run'
        from /home/ec2-user/.rvm/gems/ruby-2.5.3/gems/spring-2.0.2/lib/spring/application/boot.rb:19:in `<top (required)>'
        from /home/ec2-user/.rvm/rubies/ruby-2.5.3/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:54:in `require'
        from /home/ec2-user/.rvm/rubies/ruby-2.5.3/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:54:in `require'
        from -e:1:in `<main>'

Answer 1

Error loading the 'sqlite3' Active Record adapter. Missing a gem it depends on? can't activate sqlite3 (~> 1.3.6), already activated sqlite3-1.4.0. Make sure all dependencies are added to Gemfile. (LoadError)

と書かれているため、Gemfileでsqliteのバージョンを指定してみてはいかがでしょうか
今回の場合は、gem 'sqlite3'やgem 'sqlite3', '1.4.0'等のように書いてあると思いますが、gem 'sqlite3', '~> 1.3.6'にすると解決するかもしれません。