add Axis, Category and Subject

db/migrate/20220721123241_create_categories.rb

@@ -0,0 +1,11 @@
+class CreateCategories < ActiveRecord::Migration[7.0]
+  def change
+    create_table :categories do |t|
+      t.string :name
+
+      t.timestamps
+    end
+
+    add_index(:categories, :name, unique: true)
+  end
+end

db/migrate/20220721123254_create_axes.rb

@@ -0,0 +1,11 @@
+class CreateAxes < ActiveRecord::Migration[7.0]
+  def change
+    create_table :axes do |t|
+      t.string :name
+
+      t.timestamps
+    end
+
+    add_index(:axes, :name, unique: true)
+  end
+end

db/migrate/20220721123327_create_subjects.rb

@@ -0,0 +1,13 @@
+class CreateSubjects < ActiveRecord::Migration[7.0]
+  def change
+    create_table :subjects do |t|
+      t.string :name
+      t.references :category, null: false, foreign_key: true
+      t.references :axis, null: false, foreign_key: true
+
+      t.timestamps
+    end
+
+    add_index(:subjects, :name, unique: true)
+  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[7.0].define(version: 2022_07_21_015136) do
+ActiveRecord::Schema[7.0].define(version: 2022_07_21_123327) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -28,6 +28,31 @@ ActiveRecord::Schema[7.0].define(version: 2022_07_21_015136) do
     t.index ["resource_type", "resource_id"], name: "index_active_admin_comments_on_resource"
   end
 
+  create_table "axes", force: :cascade do |t|
+    t.string "name"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["name"], name: "index_axes_on_name", unique: true
+  end
+
+  create_table "categories", force: :cascade do |t|
+    t.string "name"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["name"], name: "index_categories_on_name", unique: true
+  end
+
+  create_table "subjects", force: :cascade do |t|
+    t.string "name"
+    t.bigint "category_id", null: false
+    t.bigint "axis_id", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["axis_id"], name: "index_subjects_on_axis_id"
+    t.index ["category_id"], name: "index_subjects_on_category_id"
+    t.index ["name"], name: "index_subjects_on_name", unique: true
+  end
+
   create_table "users", force: :cascade do |t|
     t.string "email", default: "", null: false
     t.string "encrypted_password", default: "", null: false
@@ -41,4 +66,6 @@ ActiveRecord::Schema[7.0].define(version: 2022_07_21_015136) do
     t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
 
+  add_foreign_key "subjects", "axes"
+  add_foreign_key "subjects", "categories"
 end