fix the issue on github #157.

directly force_encoding is wrong,
must detect the file string's encoding.
then force_encoding the string to it's encoding.
last convert it to utf-8.

app/helpers/commits_helper.rb

@@ -1,4 +1,5 @@
 module CommitsHelper
+  include Utils::CharEncode
   def diff_line(line, line_new = 0, line_old = 0)
     full_line = html_escape(line.gsub(/\n/, ''))
     color = if line[0] == "+"

app/models/commit.rb

@@ -1,4 +1,6 @@
 class Commit
+  include Utils::CharEncode
+
   attr_accessor :commit
   attr_accessor :head
 
@@ -20,7 +22,7 @@ class Commit
   end
 
   def safe_message
-    message.force_encoding(Encoding::UTF_8)
+    encode(message)
   end
 
   def created_at
@@ -28,10 +30,10 @@ class Commit
   end
 
   def author_email
-    author.email.force_encoding(Encoding::UTF_8)
+    encode(author.email)
   end
 
   def author_name
-    author.name.force_encoding(Encoding::UTF_8)
+    encode(author.name)
   end
 end

app/views/commits/_text_file.html.haml

@@ -2,7 +2,7 @@
 - line_new = 0
 - lines_arr = diff.diff.lines.to_a
 - lines_arr.each do |line|
-  - line.force_encoding(Encoding::UTF_8)
+  - encode(line)
   - next if line.match(/^--- \/dev\/null/)
   - next if line.match(/^--- a/)
   - next if line.match(/^\+\+\+ b/)