Use github url for homepage of log4r [ci skip]

activerecord/README.rdoc

@@ -130,7 +130,7 @@ This would also define the following accessors: `Product#name` and
  SQLite3[link:classes/ActiveRecord/ConnectionAdapters/SQLite3Adapter.html].
 
 
-* Logging support for Log4r[http:https://log4r.rubyforge.org] and Logger[http:https://www.ruby-doc.org/stdlib/libdoc/logger/rdoc].
+* Logging support for Log4r[https:https://github.com/colbygk/log4r] and Logger[http:https://www.ruby-doc.org/stdlib/libdoc/logger/rdoc].
 
  ActiveRecord::Base.logger = ActiveSupport::Logger.new(STDOUT)
  ActiveRecord::Base.logger = Log4r::Logger.new('Application Log')