Merge branch 'eslint' into 'master'

Add ESLint

## What does this MR do?

- create `package.json`
- add ESLint dependencies to `package.json`
- add JavaScript linting to CI
- add Rake task `lint:javascript`as alias for `eslint` (which itself is an alias for `npm run eslint`)

## Are there points in the code the reviewer needs to double check?

Probably not.

## Why was this MR needed?

My hovercraft was full of eels.

## What are the relevant issue numbers?

- https://gitlab.com/gitlab-org/gitlab-ce/issues/13224#note_12537431
- https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5006#note_13255658


See merge request !5445

1 files changed, 1 insertions, 0 deletions

diff --git a/app/assets/javascripts/users_select.js b/app/assets/javascripts/users_select.js
index da6a59bcf97..3847278e80a 100644
--- a/app/assets/javascripts/users_select.js
+++ b/app/assets/javascripts/users_select.js
@@ -1,3 +1,4 @@
+/* eslint-disable */
 (function() {
   var bind = function(fn, me){ return function(){ return fn.apply(me, arguments); }; },
     slice = [].slice;