migrations for state

db/migrate/20160808114841_create_states.rb

@@ -0,0 +1,21 @@
+Sequel.migration do
+  up do
+    create_table :states do
+      Uuid     :id, primary_key: true, default: 'uuid_generate_v4()'.lit
+      DateTime :created_at, default: Sequel::CURRENT_TIMESTAMP
+      DateTime :updated_at, default: Sequel::CURRENT_TIMESTAMP
+      String   :json, null: false, type: 'json', default: '{}'
+
+      foreign_key :user_id, :users, type: :uuid, null: false, on_delete: :cascade
+      foreign_key :visualization_id, :visualizations, type: :uuid, null: false, on_delete: :cascade
+    end
+
+    alter_table :states do
+      add_index [:visualization_id, :user_id]
+    end
+  end
+
+  down do
+    drop_table :states
+  end
+end

db/migrate/20160808114842_add_state_id_to_visualizations.rb

@@ -0,0 +1,13 @@
+Sequel.migration do
+  up do
+    alter_table :visualizations do
+      add_foreign_key :state_id, :states, type: 'uuid', null: true
+    end
+  end
+
+  down do
+    alter_table :visualizations do
+      drop_column :state_id
+    end
+  end
+end