added support for changing the location of the .git root

Author: dancostalis

lib/code_climate/test_reporter/configuration.rb

@@ -19,7 +19,7 @@ def self.configuration
     end
 
     class Configuration
-      attr_accessor :branch, :logger, :profile, :path_prefix, :gzip_request
+      attr_accessor :branch, :logger, :profile, :path_prefix, :gzip_request, :git_dir
 
       def initialize
         @gzip_request = true

lib/code_climate/test_reporter/git.rb

@@ -49,6 +49,7 @@ def git(command)
         end
 
         def git_dir
+          return CodeClimate::TestReporter.configuration.git_dir unless CodeClimate::TestReporter.configuration.git_dir.nil?
           defined?(Rails) ? Rails.root : '.'
         end
       end