Rails Instance Variables

I'm working on creating a survey app where surveys can have many questions and questions can have many surveys. What I'd like to do is on the survey show page display a button "Add new question" that allows a user to add a new question to that survey. So in my code I send the survey id like this:

<%= link_to "Add Question", new_question_path(:survey_id => @survey.id)%>

Then I can set @survey using the params I'm sending in my question controller. This is working fine in my :new method, but is throwing a nil error when I try to call in the :create method. I believe this is because a new instance of the controller is getting created which no longer has access to the :survey_id param I sent initially.

So I'm wondering if there is anyway to pass along the params to the next instance of the controller? Or is there a better way to send which survey should be set for that question? Is this something I could "save" in a hidden field? I thought about trying to save something in my model, but to save a question earlier would require me to remove the validations I have.

Here's my question_controller:

class QuestionsController < ApplicationController
  before_action :set_question, only: [:show, :edit, :update, :destroy]
  before_action :set_survey, only: [:new, :create]
  # GET /questions
  # GET /questions.json
  def index
    @questions = Question.all
  end

  # GET /questions/1
  # GET /questions/1.json
  def show
    @answers = @question.answers
  end

  # GET /questions/new
  def new
    @question = Question.new
  end

  # GET /questions/1/edit
  def edit
  end

  # POST /questions
  # POST /questions.json
  def create
    @question = Question.new(question_params)

    respond_to do |format|
      if @question.save
        @survey.questions << @question 
        format.html { redirect_to @question, notice: 'Question was successfully created.' }
        format.json { render action: 'show', status: :created, location: @question }
      else
        format.html { render action: 'new' }
        format.json { render json: @question.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /questions/1
  # PATCH/PUT /questions/1.json
  def update
    respond_to do |format|
      if @question.update(question_params)
        format.html { redirect_to @question, notice: 'Question was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @question.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /questions/1
  # DELETE /questions/1.json
  def destroy
    @question.destroy
    respond_to do |format|
      format.html { redirect_to questions_url }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_question
      @question = Question.find(params[:id])
    end

    def set_survey
      @survey = Survey.find(params[:survey_id])
      flash[:alert] = "Survey is " + @survey.to_s
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def question_params
      params.require(:question).permit(:title, :single_response, :surveys, :surveytizations)
    end
end

And the form I'm creating the question with:

<%= form_for(@question) do |f| %>
  <% if @question.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@question.errors.count, "error") %> prohibited this question from being saved:</h2>

      <ul>
      <% @question.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :title %><br>
    <%= f.text_field :title %>
  </div>
  <div class="field">
    <%= f.label :single_response %><br>
    <%= f.check_box :single_response %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

Thanks! Any help is very much appreciated!

UPDATE:

I was able to work using Rails.cache.write/Rails.cache.read - How to pass values between controller methods

Is there anything wrong with doing it that way or is that the best route?