A simple photo model controller with complete CRUD.

photo.rb

class Photo < ActiveRecord::Base
  
end

photos_controller.rb

class PhotosController < ApplicationController
  
  def new
    @new_photo = Photo.new
  end
  
  def create
    @new_photo = Photo.new(photo_params)
    if @new_photo.save
      redirect_to photos_path
    else
      render :new
    end
  end
  
  def index
    @photos = Photo.all
  end
  
  def show
    @photo = Photo.find(params[:id])
  end
  
  def edit
    @photo = Photo.find(params[:id])
  end
  
  def update
    @photo = Photo.find(params[:id])
    if @photo.update(photo_params)
      redirect_to photo_path
    else
      render :edit
    end
  end
  
  def destroy
    @photo = Photo.find(params[:id])
    if @photo.destroy
      redirect_to photos_path
    else
      render :show
    end
  end
  
  private
  
  def photo_params
    params.require(:photo).permit!
  end
  
end