【Rails6】deviseを使用しモデルを二つ作成し、どちらか片方のidを取得する方法

class CreateCommunities < ActiveRecord::Migration[6.0]
  def change
    create_table :communities do |t|
      t.string     :community_title,   null: false
      t.text       :community_profile, null: false
      t.references :store,             null: false, foreign_key: true
      t.references :user,              null: false, foreign_key: true

      t.timestamps
    end
  end
end

class Community < ApplicationRecord

  belongs_to :store
  belongs_to :user
  has_one_attached :image

  with_options presence: true do
    validates :community_title
  end
end

class CommunitiesController < ApplicationController
  def index
    @communities = Community.page(params[:page]).per(1)
  end

  def new
    @community = Community.new
  end

  def create
    @community = Community.create(community_params)
    if @community.save
      redirect_to root_path
    else
      render :new
    end
  end

  private

  def community_params
    params.require(:community).permit(:community_title, :community_profile, :image).merge(user_id: current_user.id, store_id: current_store.id)
  end

end

<%= render "shared/header" %>

<div id="community_new">
  <h2>コミュニティを作成</h2>
  <%= form_with(model: @community, local: true) do |f|%>

    <div class="community_new_field">
      <label>コミュニティ名<span>必須</span></label><br>
      <%= f.text_field :community_title %>
    </div>

    <div class="community_new_field">
      <label>プロフィール文<span>必須</span></label><br>
      <%= f.text_area :community_profile %>
    </div>

    <div class="community_new_field">
    <label>サムネイル画像<span>必須</span></label><br>
    <%= f.file_field :image, class: "community_img" %>
  </div>

  <div class="community_new_action">
    <%= f.submit "作成する" %>
  </div>

  <% end %>
</div>

<%= render "shared/footer" %>