Put RailsVersion into autoloaded path

Also configure it for the next rails version

app/lib/rails_version.rb

@@ -0,0 +1,14 @@
+# Check which Rails version is used by the application
+#
+# This allows code to be migrated to a newer version of Rails while keeping the old code around
+# until the migration to the newer Rails version is done.
+#
+# Use this module in combination with the gem next_rails and its Gemfile.next/Gemfile.next.lock.
+#
+# Methods of this module must match whatever Rails version is defined in Gemfile.next.lock.
+# Matching on major and minor versions should be enough for most migrations.
+module RailsVersion
+  def self.next?
+    Rails::VERSION::MAJOR == 7 && Rails::VERSION::MINOR == 2
+  end
+end