Adds rank to categories so you can set sorting

app/models/category.rb

@@ -2,4 +2,6 @@ class Category < ApplicationRecord
   validates_presence_of :name, :color
 
   has_many :expenses
+
+  default_scope { order(rank: :asc, id: :asc) }
 end

db/migrate/20210822212320_adds_order_to_categories.rb

@@ -0,0 +1,5 @@
+class AddsOrderToCategories < ActiveRecord::Migration[6.1]
+  def change
+    add_column :categories, :rank, :integer, default: 0
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2019_10_05_195440) do
+ActiveRecord::Schema.define(version: 2021_08_22_212320) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -21,6 +21,7 @@
     t.datetime "created_at", precision: 6, null: false
     t.datetime "updated_at", precision: 6, null: false
     t.integer "monthly_goal", default: 0
+    t.integer "rank", default: 0
   end
 
   create_table "expenses", force: :cascade do |t|