title: Ruby cannot load such file - active_support/core_ext/object/blank
body: <p>I was trying to run <code>brew doctor</code> but system popped up error of</p>
  
  <blockquote>
    <p>/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in
    `require': cannot load such file --
    active_support/core_ext/object/blank (LoadError)</p>
  </blockquote>
  
  <p>Searched online and another post suggested to just "gem install activesupport" but then I ran into error of:</p>
  
  <pre><code>ERROR:  Error installing activesupport:
      i18n requires Ruby version &gt;= 2.3.0.
  </code></pre>
  
  <p>I also tried to rvm install ruby-2.3.0 but the same error popped again</p>
  
  <pre><code>[2019-02-26 10:07:41] requirements_osx_brew_libs_install
  requirements_osx_brew_libs_install ()  { 
      brew install "$@" --force || { 
          \typeset ret=$?;
          requirements_osx_brew_libs_error "installation";
          return $ret
      } } current path: /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib
  PATH=/Users/{user_name}/.aw/pex_resources/scripts/binaries:/usr/local/sbin:/Users/fengjiao/.rbenv/shims:/Users/{user_name}/.nvm/v0.10.32/bin:/Users/fengjiao/bin:/usr/local/sbin:/usr/local/bin:/Users/{user_name}/.rbenv/shims:/Users/{user_name}/.nvm/v0.10.32/bin:/Users/{user_name}/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/munki:/opt/X11/bin:/Users/fengjiao/gocode/bin:/Users/{user_name}/.rvm/bin
  command(10): requirements_osx_brew_libs_install autoconf automake
  libtool pkg-config coreutils libyaml readline libksba openssl@1.1
  ++ brew install autoconf automake libtool pkg-config coreutils libyaml readline libksba openssl@1.1 --force
  /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in
  `require': cannot load such file --
  active_support/core_ext/object/blank (LoadError)    from
  /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in
  `require'   from /usr/local/Homebrew/Library/Homebrew/global.rb:10:in
  `&lt;top (required)&gt;'  from
  /usr/local/Homebrew/Library/Homebrew/brew.rb:21:in `require_relative'
      from /usr/local/Homebrew/Library/Homebrew/brew.rb:21:in `&lt;main&gt;'
  ++ typeset ret=1
  ++ requirements_osx_brew_libs_error installation
  ++ rvm_warn 'There were package installation errors, make sure to read the log.
  
  Try `brew tap --repair` and make sure `brew doctor` looks reasonable.
  </code></pre>