Also add an "outdent" option

Not requested at this time, but easy enough to implement.

indent/ruby.vim

@@ -14,7 +14,7 @@ endif
 let b:did_indent = 1
 
 if !exists('g:ruby_indent_private_protected_style')
-  " Possible values: "normal", "indent"
+  " Possible values: "normal", "indent", "outdent"
   let g:ruby_indent_private_protected_style = 'normal'
 endif
 
@@ -367,15 +367,22 @@ function GetRubyIndent(...)
   let line = getline(clnum)
   let ind = -1
 
+  " If this line is a private/protected keyword, align according to the
+  " closest class declaration.
   if g:ruby_indent_private_protected_style == 'indent'
-    " If this line is a private/protected keyword, align according to the
-    " closest class declaration.
     if s:Match(clnum, s:private_protected_regex)
       let class_line = s:SearchCode(s:class_regex, 'Wb')
       if class_line > 0
         return indent(class_line) + &sw
       endif
     endif
+  elseif g:ruby_indent_private_protected_style == 'outdent'
+    if s:Match(clnum, s:private_protected_regex)
+      let class_line = s:SearchCode(s:class_regex, 'Wb')
+      if class_line > 0
+        return indent(class_line)
+      endif
+    endif
   endif
 
   " If we got a closing bracket on an empty line, find its match and indent
@@ -454,7 +461,7 @@ function GetRubyIndent(...)
   let line = getline(lnum)
   let ind = indent(lnum)
 
-  if g:ruby_indent_private_protected_style == 'indent'
+  if g:ruby_indent_private_protected_style == 'indent' || g:ruby_indent_private_protected_style == 'outdent'
     " If the previous line was a private/protected keyword, add a level of indent
     if s:Match(lnum, s:private_protected_regex)
       return indent(s:GetMSL(lnum)) + &sw

spec/indent/private_protected_spec.rb

@@ -1,6 +1,10 @@
 require 'spec_helper'
 
 describe "Indenting" do
+  after :each do
+    vim.command 'let g:ruby_indent_private_protected_style = "normal"'
+  end
+
   specify "default public/private indenting" do
     assert_correct_indenting <<-EOF
       class One
@@ -53,4 +57,38 @@ def three
       end
     EOF
   end
+
+  specify "outdented public/private" do
+    vim.command 'let g:ruby_indent_private_protected_style = "outdent"'
+
+    assert_correct_indenting <<-EOF
+      class One
+        def two
+        end
+
+      protected
+
+        def three
+        end
+
+      private
+
+        def four
+        end
+      end
+    EOF
+
+    assert_correct_indenting <<-EOF
+      class One
+        def two
+        end
+
+        private :two
+        protected :two
+
+        def three
+        end
+      end
+    EOF
+  end
 end