Unsure if association is working in my rails app - ruby-on-rails

Question

My app has users and users are able to post links to my app. I have an association set up so that a user has many :links and links belong_to a user (see below for models). Now I am trying to get the users email to appear in the show template and I am getting a nil value for Link.user for new links. Can someone maybe shed some light as to why? Is my association incorrect? The user has been logged in when posting links.
User model:
class User < ActiveRecord::Base
has_many :links
acts_as_voter
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
end
Link model:
class Link < ActiveRecord::Base
belongs_to :user
acts_as_votable
attr_accessor :avatar
mount_uploader :avatar, AvatarUploader
end
show.html.erb:
<%= time_ago_in_words(#link.created_at) %> by <%= #link.user.try(:email) %>
Schema:
create_table "links", force: :cascade do |t|
t.string "title"
t.string "url"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "user_id"
end
create_table "users", force: :cascade do |t|
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.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
Link creation in Links controller;
def new
#link = Link.new
end
def create
#link = Link.new(link_params)
if #link.save
redirect_to root_path
else
render 'new'
end
end
private
def link_params
params.require(:link).permit(:title, :url, :avatar)
end

Answer 1

Make sure the links are actually being assigned to a user when created.
Using the rails console. Try looping through the links and making sure they have user_ids:
in the rails console:
ap Link.all.map(&:user)
If they are indeed owned by a user
<%= #link.user.email %>
should print out the email.
You should be able to do something like this in your controller:
#user.links << params[:new_link]
Make sure that much is working.

Answer 2

You are using devise. Inside your Link controller, you have to authenticate your logged on user.
# app/controllers/links_controller.rb
before_action :authenticate_user!
def create
#link = current_user.links.new(link_params)
if #link.save
redirect_to root_path
else
render 'new' # generally this is a render 'edit'
end
end
I truncated the file here. Please read the devise manual