add elm syntax and language server support

nix/home.nix

@@ -145,6 +145,17 @@ in {
       LanguageClient-neovim
       deoplete-nvim
       papercolor-theme
+      {
+        elm-vim-syntax = pkgs.vimUtils.buildVimPlugin {
+          name = "elm-vim-syntax";
+          src = pkgs.fetchFromGitHub {
+            owner = "andys8";
+            repo = "vim-elm-syntax";
+            rev = "d614325a037982489574012e4db04d7f8f134c17";
+            sha256 = "1wjv4z5wikh9kzgklg1b4rwsjwqnmvzppqs4hsqx3pyv8g0khdk1";
+          };
+        };
+      }.elm-vim-syntax
     ];
 
     extraConfig = ''
@@ -179,6 +190,17 @@ in {
       " Deoplete
       let g:deoplete#enable_at_startup = 1
 
+      " LanguageClient-neovim
+      let g:LanguageClient_serverCommands = {
+        \ 'elm': ['elm-language-server', '--stdio'],
+        \ }
+
+      let g:LanguageClient_rootMarkers = {
+        \ 'elm': ['elm.json'],
+        \ }
+
+      let g:LanguageClient_loggingFile =  expand('~/.local/share/nvim/LanguageClient.log')
+
       " Indent guides
       let g:indent_guides_enable_on_vim_startup = 1
       let g:indent_guides_start_level = 2