Vim setting with vundle

.vimrc

set nocompatible              " be iMproved, required
filetype off                  " required

" set the runtime path to include Vundle and initialize
set rtp+=~/.vim/bundle/Vundle.vim
call vundle#begin()
" alternatively, pass a path where Vundle should install plugins
"call vundle#begin('~/some/path/here')

" let Vundle manage Vundle, required
Plugin 'VundleVim/Vundle.vim'

Plugin 'ycm-core/YouCompleteMe'
Plugin 'Raimondi/delimitMate'
Plugin 'joshdick/onedark.vim'
Plugin 'Lokaltog/vim-powerline'


" All of your Plugins must be added before the following line
call vundle#end()            " required
filetype plugin indent on    " required
" To ignore plugin indent changes, instead use:
"filetype plugin on
"
" Brief help
" :PluginList       - lists configured plugins
" :PluginInstall    - installs plugins; append `!` to update or just :PluginUpdate
" :PluginSearch foo - searches for foo; append `!` to refresh local cache
" :PluginClean      - confirms removal of unused plugins; append `!` to auto-approve removal
"
" see :h vundle for more details or wiki for FAQ
" Put your non-Plugin stuff after this line
""""""""""""""""""""""""""""""""""""""""""""""""""""
" Custom Setting
set t_Co=256
set ai et ci pi sts=-1 sw=4 ts=4
set nu
syntax enable
set backspace=indent,eol,start
let g:ycm_global_ycm_extra_conf = '/Users/Jerry/.ycm_extra_conf.py'
colorscheme onedark
set guifont=Fira\ Code\ 14
let g:Powerline_symbols = 'fancy'

.ycm_extra_conf.py

def Settings( **kwargs ):
    return {
            'flags': [ '-Wall', '-Wextra', '-fsyntax-only', '-std=c++14' ],
    }