db: recreate post versions and pool versions tables.

Add the post and pool versions tables back. Currently only used by the
test suite to make it easier to run. Not yet used for production.

db/migrate/20210921164936_recreate_post_versions.rb

@@ -0,0 +1,20 @@
+class RecreatePostVersions < ActiveRecord::Migration[6.1]
+  def change
+    create_table :post_versions do |t|
+      t.timestamps null: false, index: true
+      t.references :post, null: false, index: true
+      t.references :updater, null: false, index: true
+      t.inet       :updater_ip_addr, null: false
+      t.integer    :version, null: false, default: 1, index: true
+      t.boolean    :parent_changed, null: false, default: false, index: true
+      t.boolean    :rating_changed, null: false, default: false, index: true
+      t.boolean    :source_changed, null: false, default: false, index: true
+      t.integer    :parent_id
+      t.string     :rating, limit: 1, null: false
+      t.text       :source, null: false, default: ""
+      t.text       :tags, null: false, default: ""
+      t.text       :added_tags, null: false, array: true, default: [], index: true
+      t.text       :removed_tags, null: false, array: true, default: [], index: true
+    end
+  end
+end

db/migrate/20210921170444_recreate_pool_versions.rb

@@ -0,0 +1,21 @@
+class RecreatePoolVersions < ActiveRecord::Migration[6.1]
+  def change
+    create_table :pool_versions do |t|
+      t.timestamps null: false, index: true
+      t.references :pool, null: false, index: true
+      t.references :updater, null: false, index: true
+      t.inet       :updater_ip_addr, null: false
+      t.integer    :version, default: 1, null: false
+      t.text       :name, null: false
+      t.text       :description, default: "", null: false
+      t.string     :category, null: false
+      t.boolean    :is_active, default: true, null: false
+      t.boolean    :is_deleted, default: false, null: false
+      t.boolean    :description_changed, default: false, null: false, index: true
+      t.boolean    :name_changed, default: false, null: false, index: true
+      t.integer    :post_ids, array: true, default: [], null: false, index: true
+      t.integer    :added_post_ids, array: true, default: [], null: false, index: true
+      t.integer    :removed_post_ids, array: true, default: [], null: false, index: true
+    end
+  end
+end