Strip code indents (two spaces or one tab) if present.

lib/gollum/markup.rb

@@ -321,7 +321,10 @@ module Gollum
       @codemap.each do |id, spec|
         lang = spec[:lang]
         code = spec[:code]
-        data.sub!(id, Gollum::Albino.new(code, lang).colorize)
+        if code.all? { |line| line =~ /^(  |\t)/ }
+          code.gsub!(/^(  |\t)/m, '')
+        end
+        data.gsub!(id, Gollum::Albino.new(code, lang).colorize)
       end
       data
     end

test/test_markup.rb

@@ -270,6 +270,22 @@ context "Markup" do
     assert_equal output, rendered
   end
 
+  test "code blocks with two-space indent" do
+    content = "a\n\n```ruby\n  x = 1\n```\n\nb"
+    output = "<p>a</p>\n\n<div class=\"highlight\"><pre>" +
+             "<span class=\"n\">x</span> <span class=\"o\">=</span> " +
+             "<span class=\"mi\">1</span>\n</pre>\n</div>\n\n<p>b</p>"
+    compare(content, output)
+  end
+
+  test "code blocks with one-tab indent" do
+    content = "a\n\n```ruby\n\tx = 1\n```\n\nb"
+    output = "<p>a</p>\n\n<div class=\"highlight\"><pre>" +
+             "<span class=\"n\">x</span> <span class=\"o\">=</span> " +
+             "<span class=\"mi\">1</span>\n</pre>\n</div>\n\n<p>b</p>"
+    compare(content, output)
+  end
+
   test "escaped wiki link" do
     content = "a '[[Foo]], b"
     output = "<p>a [[Foo]], b</p>"