fix error running under Rack
Merge pull request #384 from tdiary/fix_error_under_rack

fix error running under Rack
fix error using IO gems with file cache #386
fix error using IO gems
update settings for heroku
require hikidoc
cosmetic
update dependency
update docs for twitter login with omniauth
workaround for TDiary::Cache initialization
update test document
update latest dependency
update latest dependency for PaaS
bump version to 4.0.2
redcarpet is needed to generate document
revive tmp dir
update dependency
speed up on travis
fix error running under Rack (#375)
define customize paths in TDiary::Extensions