Added vimtex plugin with YCM completions.

vim/vimrc

@@ -104,6 +104,7 @@ if filereadable("/etc/vim/vimrc.local")
 endif
 
 syntax spell toplevel
+let g:tex_flavor = 'latex'
 
 function! BuildYCM(info)
 	" info is a dictionary with 3 fields
@@ -133,6 +134,7 @@ call plug#begin('~/.vim/vim-plug')
 
 Plug 'scrooloose/nerdtree', { 'on': 'NERDTreeToggle' }
 Plug 'ycm-core/YouCompleteMe', { 'do': function('BuildYCM'), 'on': [] }
+Plug 'lervag/vimtex'
 
 call plug#end()
 
@@ -142,3 +144,9 @@ map  :NERDTreeToggle
 let g:ycm_autoclose_preview_window_after_insertion = 1
 let g:ycm_autoclose_preview_window_after_completion = 1
 
+" enable vimtex completions for YCM
+if !exists('g:ycm_semantic_triggers')
+	let g:ycm_semantic_triggers = {}
+endif
+autocmd VimEnter * let g:ycm_semantic_triggers.tex=g:vimtex#re#youcompleteme
+