rails5.1.7でモデルを作成しようとするとloaderrorがでます

前提・実現したいこと

ここに質問の内容を詳しく書いてください。
（例）PHP(CakePHP)で●●なシステムを作っています。
■■な機能を実装中に以下のエラーメッセージが発生しました。

発生している問題・エラーメッセージ

/home/ec2-user/.rvm/gems/ruby-2.6.0/gems/ffi-1.10.0/lib/ffi.rb:6:in `require': libffi.so.6: cannot open shared object file: No such file or directory - /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/ffi-1.10.0/lib/ffi_c.so (LoadError)


### 該当のソースコード

```rails 5.1.7 ruby 2.6.0
ソースコード

rails generate model Micropost content:text user:references
/home/ec2-user/.rvm/gems/ruby-2.6.0/gems/ffi-1.10.0/lib/ffi.rb:6:in `require': libffi.so.6: cannot open shared object file: No such file or directory - /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/ffi-1.10.0/lib/ffi_c.so (LoadError)

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/ffi-1.10.0/lib/ffi.rb:6:in `rescue in <top (required)>'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/ffi-1.10.0/lib/ffi.rb:3:in `<top (required)>'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/rb-inotify-0.10.0/lib/rb-inotify/native.rb:1:in `require'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/rb-inotify-0.10.0/lib/rb-inotify/native.rb:1:in `<top (required)>'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/rb-inotify-0.10.0/lib/rb-inotify.rb:2:in `require'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/rb-inotify-0.10.0/lib/rb-inotify.rb:2:in `<top (required)>'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/adapter/linux.rb:30:in `require'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/adapter/linux.rb:30:in `_configure'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/adapter/base.rb:45:in `block in configure'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/adapter/base.rb:40:in `each'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/adapter/base.rb:40:in `configure'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/adapter/base.rb:63:in `start'

from /home/linuxbrew/.linuxbrew/Cellar/ruby/2.6.3/lib/ruby/2.6.0/forwardable.rb:230:in `start'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/listener.rb:68:in `block in class:Listener'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/fsm.rb:121:in `instance_eval'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/fsm.rb:121:in `call'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/fsm.rb:91:in `transition_with_callbacks!'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/fsm.rb:57:in `transition'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/listen-3.1.5/lib/listen/listener.rb:91:in `start'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/spring-watcher-listen-2.0.1/lib/spring/watcher/listen.rb:27:in `start'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/spring-2.0.2/lib/spring/application.rb:80:in `start_watcher'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/spring-2.0.2/lib/spring/application.rb:89:in `preload'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/spring-2.0.2/lib/spring/application.rb:153:in `serve'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/spring-2.0.2/lib/spring/application.rb:141:in `block in run'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/spring-2.0.2/lib/spring/application.rb:135:in `loop'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/spring-2.0.2/lib/spring/application.rb:135:in `run'

from /home/ec2-user/.rvm/gems/ruby-2.6.0/gems/spring-2.0.2/lib/spring/application/boot.rb:19:in `<top (required)>'

from /home/linuxbrew/.linuxbrew/Cellar/ruby/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'

from -e:1:in `<main>'

試したこと

rubyのバージョンを2.6.3にしたり2.6.0にしたりした

補足情報（FW/ツールのバージョンなど）

dbでmysqlをデフォルトのdbにしてアプリ作成→rubyの最新バージョンではエラーが出る、なんかターミナルのコマンド全部おかしくなる（エラーメッセージ：You must use Bundler 2 or greater with this lockfile）→rubyのバージョンを変える為rbenv と　ruby buildの二つが必要になる→それをインストールするためにhomebrewをcloud9内にインストール→さっきの二つをインストール→モデル作成→作成できず上記のエラーが発生