chore: 不要なActive Support依存を削除

- プラグインから未使用のrequire文を削除
- Gemfileからactivesupport gemを削除
- bundle installで依存関係を元の状態に戻した

Author: yasulab

Gemfile

@@ -12,7 +12,6 @@ group :jekyll_plugins do
   gem 'jekyll-sitemap'
   gem 'jekyll-liquify'
   gem 'jekyll-redirect-from'
-  gem 'activesupport' # For time calculations in plugins
 
   # No need this gem because we build by GitHub Actions and serve on Pages.
   # gem 'github-pages'

Gemfile.lock

@@ -2,19 +2,6 @@ GEM
   remote: https://rubygems.org/
   specs:
     Ascii85 (2.0.1)
-    activesupport (8.0.2.1)
-      base64
-      benchmark (>= 0.3)
-      bigdecimal
-      concurrent-ruby (~> 1.0, >= 1.3.1)
-      connection_pool (>= 2.2.5)
-      drb
-      i18n (>= 1.6, < 2)
-      logger (>= 1.4.2)
-      minitest (>= 5.1)
-      securerandom (>= 0.3)
-      tzinfo (~> 2.0, >= 2.0.5)
-      uri (>= 0.13.1)
     addressable (2.8.7)
       public_suffix (>= 2.0.2, < 7.0)
     afm (0.2.2)
@@ -25,17 +12,14 @@ GEM
       metrics (~> 0.12)
       traces (~> 0.15)
     base64 (0.2.0)
-    benchmark (0.4.1)
     bigdecimal (3.1.9)
     colorator (1.1.0)
     concurrent-ruby (1.3.5)
-    connection_pool (2.5.4)
     console (1.30.2)
       fiber-annotation
       fiber-local (~> 1.1)
       json
     csv (3.3.4)
-    drb (2.2.3)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
@@ -148,7 +132,6 @@ GEM
     metrics (0.12.2)
     mini_racer (0.18.1)
       libv8-node (~> 23.6.1.0)
-    minitest (5.25.5)
     nokogiri (1.18.9-aarch64-linux-gnu)
       racc (~> 1.4)
     nokogiri (1.18.9-aarch64-linux-musl)
@@ -202,7 +185,6 @@ GEM
       google-protobuf (~> 4.31)
     sass-embedded (1.89.0-x86_64-linux-musl)
       google-protobuf (~> 4.31)
-    securerandom (0.4.1)
     terminal-table (3.0.2)
       unicode-display_width (>= 1.1.1, < 3)
     traces (0.15.2)
@@ -213,10 +195,7 @@ GEM
       bigdecimal (~> 3.1)
     typhoeus (1.4.1)
       ethon (>= 0.9.0)
-    tzinfo (2.0.6)
-      concurrent-ruby (~> 1.0)
     unicode-display_width (2.6.0)
-    uri (1.0.3)
     webrick (1.9.1)
     yell (2.2.2)
     zeitwerk (2.7.3)
@@ -236,7 +215,6 @@ PLATFORMS
   x86_64-linux-musl
 
 DEPENDENCIES
-  activesupport
   html-proofer
   jekyll
   jekyll-feed

_plugins/time_table_generator.rb

@@ -1,6 +1,3 @@
-require 'active_support/core_ext/integer/time'
-require 'active_support/core_ext/numeric/time'
-
 module Jekyll
   module TimeTableGenerator
     # タイムテーブル表を事前に計算してイベント表形式に変換