Use rails 8 compatible active_record_union

https://github.com/brianhempel/active_record_union/issues/36

Gemfile

@@ -49,7 +49,7 @@ gem "file_exists"
 # Load rails plugins
 gem "actionpack-page_caching", ">= 1.2.0"
 gem "activerecord-import"
-gem "active_record_union"
+gem "active_record_union", :github => "brianhempel/active_record_union", :ref => "master"
 gem "bootstrap", "~> 5.3.2"
 gem "bootstrap_form", "~> 5.0"
 gem "cancancan"

Gemfile.lock

@@ -1,3 +1,11 @@
+GIT
+  remote: https://github.com/brianhempel/active_record_union.git
+  revision: 8ebe558709aabe039abd24e3e7dd4d4354a6de88
+  ref: master
+  specs:
+    active_record_union (1.3.0)
+      activerecord (>= 6.0)
+
 GEM
   remote: https://rubygems.org/
   specs:
@@ -48,8 +56,6 @@ GEM
       erubi (~> 1.11)
       rails-dom-testing (~> 2.2)
       rails-html-sanitizer (~> 1.6)
-    active_record_union (1.3.0)
-      activerecord (>= 4.0)
     activejob (8.0.1)
       activesupport (= 8.0.1)
       globalid (>= 0.3.6)
@@ -677,7 +683,7 @@ PLATFORMS
 DEPENDENCIES
   aasm
   actionpack-page_caching (>= 1.2.0)
-  active_record_union
+  active_record_union!
   activerecord-import
   addressable (~> 2.8)
   annotaterb