Merge pull request #31 from yasulab/patch-1

Update invite link

Author: znz

_config.yml

@@ -20,4 +20,4 @@ twitter:
   card: summary_large_image
   username: ruby-jp
 
-slack_invite_link: https://join.slack.com/t/ruby-jp/shared_invite/zt-1dtwm6asw-nySp8OsdZfKeowNOxKeyGQ
+slack_invite_link: https://join.slack.com/t/ruby-jp/shared_invite/zt-1h1wub6jl-s37DRnh3lPDeyCt5REr3Yw