Creating Relationships Problems [Rails 4.1.1]

I've been doing some research before requesting help from the forums, but I cannot quite find the solution to my problem. I currently have problems implementing the first name and last name in the index page as well as the 'show' page. Adding code in the following pages:

[index.html.erb]

<strong><%= status.user.first_name %></strong>

[show.html.erb]

<%= @status.user.first_name %>

seems to be, repeatedly, causing this error to appear:

undefined method `first_name' for nil:NilClass

I decided to do some research on the forums afterwords and found this piece of information, but it did not help:

[statuses_controller.rb]

    def status_params
      params.require(:status).permit(:name, :content, :user_id)
    end

I also looked at a Devise controller mentioned by Jason, but I do not know what to do with the piece of code provided. Do I simply make a Devise controller and put it in the "Controller" directory or is there something else to it?

Either way, I am stuck with adding the users first name let alone their last. Can anyone guide me through this problem?