title: I cannot install php composer in Ubuntu 16.04
body: <p>I have this error when I try to install composer:</p>
  
  <p>Some settings on your machine make Composer unable to work properly.
  Make sure that you fix the issues listed below and run this script again:</p>
  
  <p>The openssl extension is missing, which means that secure HTTPS transfers are impossible.
  If possible you should enable it or recompile php with --with-openssl</p>
  
  <p>I followed this steps from my terminal in the Downloads directory:</p>
  
  <pre><code>php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
  php -r "if (hash_file('SHA384', 'composer-setup.php') === 'e115a8dc7871f15d853148a7fbac7da27d6c0030b848d9b3dc09e2a0388afed865e6a3d6b3c0fad45c48e2b5fc1196ae') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
  php composer-setup.php
  php -r "unlink('composer-setup.php');"
  </code></pre>
  
  <p>Just like the website says. What can I do now? I'm using Laravel but I need composer first. I have seen on internet that it's something to do with extensions but I don't know how to it.</p>
  
  <p>Hope someone cal help me with this!</p>
  
  <p>Thanks in advance.</p>