Add the Reek checker for Ruby. (#490)

Add the Reek checker for Ruby.

doc/ale-ruby.txt

@@ -2,6 +2,27 @@
 ALE Ruby Integration                                         *ale-ruby-options*
 
 
+-------------------------------------------------------------------------------
+reek                                                            *ale-ruby-reek*
+
+g:ale_ruby_reek_show_context                     *g:ale_ruby_reek_show_context*
+
+  Type: |Number|
+  Default: 0
+
+  Controls whether context is included in the linter message. Defaults to off
+  because context is usually obvious while viewing a file.
+
+
+g:ale_ruby_reek_show_wiki_link                 *g:ale_ruby_reek_show_wiki_link*
+
+  Type: |Number|
+  Default: 0
+
+  Controls whether linter messages contain a link to an explanatory wiki page
+  for the type of code smell. Defaults to off to improve readability.
+
+
 -------------------------------------------------------------------------------
 rubocop                                                      *ale-ruby-rubocop*
 

doc/ale.txt

@@ -60,6 +60,7 @@ CONTENTS                                                         *ale-contents*
       mypy................................|ale-python-mypy|
       pylint..............................|ale-python-pylint|
     ruby..................................|ale-ruby-options|
+      reek................................|ale-ruby-reek|
       rubocop.............................|ale-ruby-rubocop|
     rust..................................|ale-rust-options|
       cargo...............................|ale-rust-cargo|
@@ -155,7 +156,7 @@ The following languages and tools are supported.
 * reStructuredText: 'proselint'
 * RPM spec: 'spec'
 * Rust: 'rustc' (see |ale-integration-rust|)
-* Ruby: 'rubocop'
+* Ruby: 'reek', 'rubocop'
 * SASS: 'sasslint', 'stylelint'
 * SCSS: 'sasslint', 'scsslint', 'stylelint'
 * Scala: 'scalac'