Add duration to workouts

db/migrate/20230425062935_add_duration_to_workouts.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+ROM::SQL.migration do
+  change do
+    alter_table :workouts do
+      add_column :duration, :float, null: false
+    end
+  end
+end