title: Neovim error: E492: Not an editor command: PlugInstall
body: <p>OS: Ubuntu 18.04.3 LTS</p>
  
  <p>I just installed neovim using <code>sudo apt-get install neovim</code> and added the folder and file <code>~/.config/nvim/vim.init</code>. At this moment the file has no content, but when I open up <code>nvim</code> and type <code>:PlugInstall</code> I get error: <code>E492: Not an editor command: PlugInstall</code>. I am clueless, what is going wrong?</p>