NOTE: This plugin is not maintained, in favor of LanguageServer-php-neovim, since LanguageClient-neovim has a nicer interface for language server protocol implementation. Go try it, it should work better than this plugin.
PHP completion source for nvim-completion-manager, using the powerful php-language-server.
Assumming you're using vim-plug
Plug 'roxma/nvim-cm-php-language-server', {'do': 'composer install && composer run-script parse-stubs'}