app/controllers/guests_controller.rb

@@ -10,6 +10,11 @@ class GuestsController < ApplicationController
                       .as_json(only: %i[id name status], include: { group: { only: %i[id name] } })
   end
 
+  def create
+    Guest.create!(params.require(:guest).permit(:name, :group_id, :status))
+    render json: {}, status: :created
+  end
+
   def update
     Guest.find(params[:id]).update!(params.require(:guest).permit(:name))
     render json: {}, status: :ok

config/routes.rb

@@ -4,7 +4,7 @@ Rails.application.routes.draw do
   mount Rswag::Ui::Engine => '/api-docs'
   mount Rswag::Api::Engine => '/api-docs'
   resources :groups, only: :index
-  resources :guests, only: %i[index update] do
+  resources :guests, only: %i[index create update] do
     post :bulk_update, on: :collection
   end
   resources :expenses, only: %i[index update] do

spec/requests/guests_spec.rb

@@ -52,6 +52,30 @@ RSpec.describe 'guests', type: :request do
         xit
       end
     end
+
+    post('create guest') do
+      tags 'Guests'
+      consumes 'application/json'
+      produces 'application/json'
+      parameter name: :body, in: :body, schema: {
+        type: :object,
+        required: %i[guest],
+        properties: {
+          guest: {
+            type: :object,
+            required: %i[name group_id status],
+            properties: {
+              name: { type: :string },
+              group_id: { type: :string, format: :uuid },
+              status: { type: :string, enum: Guest.statuses.keys }
+            }
+          }
+        }
+      }
+
+      response_empty_201
+      response_422
+    end
   end
 
   path '/guests/{id}' do

spec/swagger_response_helper.rb

@@ -17,6 +17,14 @@ module SwaggerResponseHelper
     end
   end
 
+  def response_empty_201
+    response(201, 'Created') do
+      produces 'application/json'
+      schema type: :object
+      xit
+    end
+  end
+
   def response_404
     response(404, 'Record not found') do
       produces 'application/json'