Add Units

db/migrate/20230602185352_create_units.rb

@@ -0,0 +1,19 @@
+class CreateUnits < ActiveRecord::Migration[7.0]
+  def change
+    create_table :units do |t|
+      t.references :user, foreign_key: true
+      t.string :symbol
+      t.string :name
+      t.decimal :multiplier, precision: 30, scale: 15
+
+      t.references :base
+      t.integer :lft, null: false
+      t.integer :rgt, null: false
+
+      t.timestamps
+    end
+    add_index :units, [:user_id, :symbol], unique: true
+    add_index :units, :lft
+    add_index :units, :rgt
+  end
+end