add roles to admin panel

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_132939) do
+ActiveRecord::Schema[7.0].define(version: 2022_07_21_133421) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -118,6 +118,20 @@ ActiveRecord::Schema[7.0].define(version: 2022_07_21_132939) do
     t.index ["user_id"], name: "index_review_requests_on_user_id"
   end
 
+  create_table "roles", force: :cascade do |t|
+    t.string "name"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["name"], name: "index_roles_on_name", unique: true
+  end
+
+  create_table "roles_users", id: false, force: :cascade do |t|
+    t.bigint "user_id", null: false
+    t.bigint "role_id", null: false
+    t.index ["role_id", "user_id"], name: "index_roles_users_on_role_id_and_user_id"
+    t.index ["user_id", "role_id"], name: "index_roles_users_on_user_id_and_role_id"
+  end
+
   create_table "subjects", force: :cascade do |t|
     t.string "name"
     t.bigint "category_id", null: false