Add erb linter (#497)

* Add eruby linter

* Update README with erb linter

* Fix example and contributions

* Remove trailing newline

* Fix for Vimscript style guide

* Eruby-linter: codereview with @w0rp
- read from stderro output_stream

* Eruby-linter: codereview => add handler for ruby

* Eruby-linter: codereview
- eruby and ruby lint use the same ruby-handler (removes
  duplicated handling logic)

* Eruby-linter: try to fix tests

ale_linters/ruby/ruby.vim

@@ -1,39 +1,10 @@
 " Author: Brandon Roehl - https://github.com/BrandonRoehl
 " Description: Ruby MRI for Ruby files
 
-function! ale_linters#ruby#ruby#Handle(buffer, lines) abort
-    " Matches patterns line the following:
-    "
-    " test.rb:3: warning: parentheses after method name is interpreted as an argument list, not a decomposed argument
-    " test.rb:8: syntax error, unexpected keyword_end, expecting end-of-input
-    let l:pattern = '\v^.+:(\d+): (warning: )?(.+)$'
-    let l:column = '\v^(\s+)\^$'
-    let l:output = []
-
-    for l:line in a:lines
-        let l:match = matchlist(l:line, l:pattern)
-        if len(l:match) == 0
-            let l:match = matchlist(l:line, l:column)
-            if len(l:match) != 0
-                let l:output[len(l:output) - 1]['col'] = len(l:match[1])
-            endif
-        else
-            call add(l:output, {
-            \   'lnum': l:match[1] + 0,
-            \   'col': 0,
-            \   'text': l:match[2] . l:match[3],
-            \   'type': empty(l:match[2]) ? 'E' : 'W',
-            \})
-        endif
-    endfor
-
-    return l:output
-endfunction
-
 call ale#linter#Define('ruby', {
 \   'name': 'ruby',
 \   'executable': 'ruby',
 \   'output_stream': 'stderr',
 \   'command': 'ruby -w -c -T1 %t',
-\   'callback': 'ale_linters#ruby#ruby#Handle',
+\   'callback': 'ale#handlers#ruby#HandleSyntaxErrors',
 \})