Allow cascade delete Unit/Quantity

Closes #32

db/migrate/20230602185352_create_units.rb

@@ -5,7 +5,7 @@ class CreateUnits < ActiveRecord::Migration[7.0]
       t.string :symbol, null: false, limit: 15
       t.text :description
       t.decimal :multiplier, null: false, precision: 30, scale: 15, default: 1.0
-      t.references :base, foreign_key: {to_table: :units}
+      t.references :base, foreign_key: {to_table: :units, on_delete: :cascade}
 
       t.timestamps null: false
     end

db/migrate/20250104194343_create_quantities.rb

@@ -4,7 +4,7 @@ class CreateQuantities < ActiveRecord::Migration[7.2]
       t.references :user, foreign_key: true
       t.string :name, null: false, limit: 31
       t.text :description
-      t.references :parent, foreign_key: {to_table: :quantities}
+      t.references :parent, foreign_key: {to_table: :quantities, on_delete: :cascade}
 
       t.timestamps null: false
 

db/schema.rb

@@ -69,11 +69,11 @@ ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
     t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
 
-  add_foreign_key "quantities", "quantities", column: "parent_id"
+  add_foreign_key "quantities", "quantities", column: "parent_id", on_delete: :cascade
   add_foreign_key "quantities", "users"
   add_foreign_key "readouts", "quantities"
   add_foreign_key "readouts", "units"
   add_foreign_key "readouts", "users"
-  add_foreign_key "units", "units", column: "base_id"
+  add_foreign_key "units", "units", column: "base_id", on_delete: :cascade
   add_foreign_key "units", "users"
 end

db/seeds/templates/units.erb

@@ -1,5 +1,5 @@
 Unit.transaction do
-  Unit.defaults.order(Unit.arel_table[:base_id].eq(nil)).delete_all
+  Unit.defaults.delete_all
   units = {}
 <% Unit.defaults.ordered.each do |unit| %>
 <%= "\n" if unit.base.nil? %>

db/seeds/units.rb

@@ -1,5 +1,5 @@
 Unit.transaction do
-  Unit.defaults.order(Unit.arel_table[:base_id].eq(nil)).delete_all
+  Unit.defaults.delete_all
 
   units = {}