Adding a select for belongs_to for an Edit Form

  @impl true
  def render(assigns) do
    ~H"""
    <div>
      <.header>
        <%= @title %>
        <:subtitle>Use this form to manage customer records in your database.</:subtitle>
      </.header>

      <.simple_form
        for={@form}
        id="customer-form"
        phx-target={@myself}
        phx-change="validate"
        phx-submit="save"
      >
        <.input field={@form[:version_id]} options={@versions} type="select" value={@form[:version_name]} label="Version" />
        <.input field={@form[:name]} type="text" label="Name" />
        <:actions>
          <.button phx-disable-with="Saving...">Save Customer</.button>
        </:actions>
      </.simple_form>
    </div>
    """
  end

  def mount(_params, _, socket) do
    versions = for version <- Builder.list_version(), do: {version.id, version.name}
    {:ok, assign(socket, :versions, versions)}
  end

I get key :versions not found in: %{__changed__: %{action: true, customer: true, fla...

I was thinking that the mount could set the property versions for the render to use?