title: Autoincrement postgre DB id field in RAILS
body: <p>I am trying to make an autoincrement id field into a postgre DB in rails. I am trying to get the maximum id and then just add +1 and pass it down to create method. I am not quite sure what I am doing wrong, but if I have 4 projects and add the 5th one, that is getting id 5, but if I delete that one and try to add another one, that's getting id 6, not 5 again. Here is my code:</p>
  
  <pre><code> # GET /admin/projects/new
    def new
      @project = Project.new
      @project.id = Project.maximum(:id).next.to_i
  
      respond_to do |format|
        format.html # new.html.erb
      end
    end
  
    # GET /admin/projects/1/edit
    def edit
      @project = Project.find(params[:id])
    end
  
    # POST /admin/projects
    def create
      @project = Project.create(params[:project])
  
      respond_to do |format|
        if @project.save
          format.html { redirect_to projects_path, notice: 'Project was successfully created.' }
        else
          format.html { render action: "new" }
        end
      end
    end
  </code></pre>
  
  <p>I tried to add <code>@project.save</code> to new, but as much as I understand, the <code>.save</code> should only be done in the create method. Any ideas will be kindly appreciated :D</p>