Introduce static version model

app/models/saved_scenario.rb

@@ -14,6 +14,9 @@ class SavedScenario < ApplicationRecord
   validates :title,       presence: true
   validates :end_year,    presence: true
   validates :area_code,   presence: true
+  validates :version, presence: true, inclusion: {
+    in: Version.all
+  }
 
   serialize :scenario_id_history, coder: YAML, type: Array
 end

app/models/version.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+# A valid version of the ETM
+class Version
+  LIST = %i[
+    latest
+  ].freeze
+
+  # All available versions. Uses ActiveRecord syntax 'all' to
+  # make future porting to db easier
+  def self.all
+    LIST
+  end
+end

db/migrate/20241014102534_create_saved_scenarios.rb

@@ -5,6 +5,7 @@ def change
       t.text :scenario_id_history
       t.string :title, null: false
       t.text :description
+      t.string :version, default: 'latest'
       t.string :area_code, null: false
       t.integer :end_year, null: false
       t.boolean :private, default: false