new.html.erb

<h1> Add a route to this gym </h1>
<br>

<%= form_for :route, url: { action: "create" }, method: 'post'  do |f| %>
    <div class="field">
      <%= f.label :route_identifier %><br>
      <%= f.text_field :route_identifier %>
    </div>
    <div class="field">
      <%= f.label :grade %><br>
      <%= f.text_field :grade %>
    </div>
    <div class="field">
      <%= f.label :route_setter_comments %><br>
      <%= f.text_field :route_setter_comments %>
    </div>
    <div class="actions">
        <%= f.submit "submit" %>
    </div>
<% end %>

routes_controller.rb

  def new
    @route = Route.new
    @gym = Gym.find(params[:gym_id]) 
  end


  def create
    if current_user.route_setter
      #binding.pry
      @gym = Gym.find(params[:gym_id])
      @route = @gym.route.new(route_params)
      if @route.save
        puts "saved"
        flash[:success]="New route #{@route.identifier} successfully added."
        redirect_to '/'
      end
    else
      flash[:error]="you do not have correct permmisions to do this, you are not a route setter"
      puts "not saved"
      render :new
    end
  end

  def route_params
    params.require(:route).permit(:identifier, :route_setter_comments, :grade)
  end

schema.rb

# This file is auto-generated from the current state of the database. Instead
# of editing this file, please use the migrations feature of Active Record to
# incrementally modify your database, and then regenerate this schema definition.
#
# Note that this schema.rb definition is the authoritative source for your
# database schema. If you need to create the application database on another
# system, you should be using db:schema:load, not running all the migrations
# from scratch. The latter is a flawed and unsustainable approach (the more migrations
# you'll amass, the slower it'll run and the greater likelihood for issues).
#
# It's strongly recommended that you check this file into your version control system.

ActiveRecord::Schema.define(version: 20180502150841) do

  create_table "climbs", force: :cascade do |t|
    t.integer "comment_id"
    t.integer "user_id"
    t.integer "route_id"
    t.text "climb_comment"
    t.boolean "completed"
    t.string "completion_type"
    t.datetime "completed_at"
    t.integer "attempt_count"
    t.integer "completed_count"
    t.integer "grade_rating"
    t.integer "enjoy_rating"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["comment_id"], name: "index_climbs_on_comment_id"
    t.index ["route_id"], name: "index_climbs_on_route_id"
    t.index ["user_id"], name: "index_climbs_on_user_id"
  end

  create_table "comments", force: :cascade do |t|
    t.integer "climb_id"
    t.integer "user_id"
    t.text "text"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["climb_id"], name: "index_comments_on_climb_id"
    t.index ["user_id"], name: "index_comments_on_user_id"
  end

  create_table "gyms", force: :cascade do |t|
    t.integer "routes_id"
    t.string "gym_name", null: false
    t.text "about"
    t.string "address"
    t.string "email"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.string "route_setter_list"
    t.string "gym_owner_list"
    t.index ["routes_id"], name: "index_gyms_on_routes_id"
  end

  create_table "memberships", force: :cascade do |t|
    t.integer "user_id"
    t.integer "gym_id"
    t.boolean "route_setter"
    t.boolean "gym_owner"
    t.boolean "climber"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["gym_id"], name: "index_memberships_on_gym_id"
    t.index ["user_id"], name: "index_memberships_on_user_id"
  end

  create_table "routes", force: :cascade do |t|
    t.integer "user_id"
    t.integer "gym_id"
    t.integer "climbs_id"
    t.integer "grade"
    t.datetime "date_set"
    t.datetime "date_removed"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["climbs_id"], name: "index_routes_on_climbs_id"
    t.index ["gym_id"], name: "index_routes_on_gym_id"
    t.index ["user_id"], name: "index_routes_on_user_id"
  end

  create_table "users", force: :cascade do |t|
    t.string "first_name", null: false
    t.string "last_name", null: false
    t.string "user_name", null: false
    t.string "email", default: "", null: false
    t.string "encrypted_password", default: "", null: false
    t.string "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.integer "sign_in_count", default: 0, null: false
    t.datetime "current_sign_in_at"
    t.datetime "last_sign_in_at"
    t.string "current_sign_in_ip"
    t.string "last_sign_in_ip"
    t.boolean "climber", default: true
    t.boolean "route_setter", default: false
    t.boolean "gym_owner", default: false
    t.integer "comment_id"
    t.integer "route_id"
    t.integer "climb_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["climb_id"], name: "index_users_on_climb_id"
    t.index ["comment_id"], name: "index_users_on_comment_id"
    t.index ["email"], name: "index_users_on_email", unique: true
    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
    t.index ["route_id"], name: "index_users_on_route_id"
  end

end

url.txt

http://127.0.0.1:3000/routes/new?gym=1

Error: Couldn't find Gym with 'id'=

how do i pass the params of the gym id, between new and create