title: Gem install wrong number of arguments (given 4, expected 1)
body: <p>When I run <code>bundle</code>, I get the following:</p>
  <pre><code>-bash: bundle: command not found
  </code></pre>
  <p>I'm not a ruby developer, but it seems like I need bundler to get some software running other people wrote. So I'm trying to get bundler using <code>gem install bundler</code>, but I get the following error:</p>
  <pre><code>ERROR:  While executing gem ... (ArgumentError)
      wrong number of arguments (given 4, expected 1)
  </code></pre>
  <p>Using <code>--backtrace</code></p>
  <pre><code>ERROR:  While executing gem ... (ArgumentError)
      wrong number of arguments (given 4, expected 1)
          /var/lib/gems/2.5.0/gems/psych-4.0.1/lib/psych.rb:323:in `safe_load'
          /usr/lib/ruby/2.5.0/rubygems/safe_yaml.rb:31:in `safe_load'
          /usr/lib/ruby/2.5.0/rubygems/package.rb:496:in `block (2 levels) in read_checksums'
          /usr/lib/ruby/2.5.0/rubygems/package.rb:495:in `wrap'
          /usr/lib/ruby/2.5.0/rubygems/package.rb:495:in `block in read_checksums'
          /usr/lib/ruby/2.5.0/rubygems/package/tar_reader.rb:116:in `seek'
          /usr/lib/ruby/2.5.0/rubygems/package.rb:494:in `read_checksums'
          /usr/lib/ruby/2.5.0/rubygems/package.rb:547:in `block (2 levels) in verify'
          /usr/lib/ruby/2.5.0/rubygems/package/tar_reader.rb:29:in `new'
          /usr/lib/ruby/2.5.0/rubygems/package.rb:546:in `block in verify'
          /usr/lib/ruby/2.5.0/rubygems/package/file_source.rb:30:in `open'
          /usr/lib/ruby/2.5.0/rubygems/package/file_source.rb:30:in `with_read_io'
          /usr/lib/ruby/2.5.0/rubygems/package.rb:545:in `verify'
          /usr/lib/ruby/2.5.0/rubygems/package.rb:526:in `spec'
          /usr/lib/ruby/2.5.0/rubygems/source/local.rb:49:in `block in load_specs'
          /usr/lib/ruby/2.5.0/rubygems/source/local.rb:43:in `each'
          /usr/lib/ruby/2.5.0/rubygems/source/local.rb:43:in `load_specs'
          /usr/lib/ruby/2.5.0/rubygems/source/local.rb:83:in `find_gem'
          /usr/lib/ruby/2.5.0/rubygems/resolver/installer_set.rb:141:in `find_all'
          /usr/lib/ruby/2.5.0/rubygems/resolver/installer_set.rb:56:in `add_always_install'
          /usr/lib/ruby/2.5.0/rubygems/dependency_installer.rb:478:in `resolve_dependencies'
          /usr/lib/ruby/2.5.0/rubygems/commands/install_command.rb:194:in `install_gem'
          /usr/lib/ruby/2.5.0/rubygems/commands/install_command.rb:255:in `block in install_gems'
          /usr/lib/ruby/2.5.0/rubygems/commands/install_command.rb:251:in `each'
          /usr/lib/ruby/2.5.0/rubygems/commands/install_command.rb:251:in `install_gems'
          /usr/lib/ruby/2.5.0/rubygems/commands/install_command.rb:158:in `execute'
          /usr/lib/ruby/2.5.0/rubygems/command.rb:313:in `invoke_with_build_args'
          /usr/lib/ruby/2.5.0/rubygems/command_manager.rb:173:in `process_args'
          /usr/lib/ruby/2.5.0/rubygems/command_manager.rb:143:in `run'
          /usr/lib/ruby/2.5.0/rubygems/gem_runner.rb:59:in `run'
          /usr/bin/gem:21:in `&lt;main&gt;'
  </code></pre>
  <ul>
  <li>ruby version:
  <code>ruby 2.5.5p157 (2019-03-15 revision 67260) [arm-linux-gnueabihf]</code>.</li>
  <li>gem version:
  2.7.6.2</li>
  <li>I'm on a raspbian linux.</li>
  </ul>