Linting Ruby right in Neovim

For Vim to lint the current file in the background and show errors directly in the editor, you need to do these three steps:

1. Install ALE (async code checker with Language Server Protocol support).

2. Setup it:

" What do we use for linting
let g:ale_linters = {
\ 'javascript': ['eslint'],
\ 'ruby': ['rubocop']
\}

let g:ale_linters_explicit = 1

" Lint Ruby files with binstub
let g:ale_ruby_rubocop_executable = 'bin/rubocop'

" Tune linter's error and warning signs
let g:ale_sign_error = '\u2022'
let g:ale_sign_warning = '\u2022'

" Let's leave a column for the signs so that the left side of the window doesn't move
let g:ale_sign_column_always = 1

3. You're beatiful!