<header>
    <div class="wrapper">
        <img src="/gfx/logo.png">
        <span>Welcome</span>
        <% if current_user %>
            <%= link_to "Log Out", logout_path %>
        <% else %>
            <%= form_tag sessions_path do %>
                <%= text_field_tag :username, nil, placeholder: "username" %>
                <%= password_field_tag :password, nil,  placeholder: "password" %>
                <%= submit_tag "Log In" %>
            <% end %>
        <% end %>
    </div>
</header>

class SessionsController < ApplicationController

private

def current_user
    @current_user ||= User.find(session[:user_id]) if session[:user_id]
end

helper_method :current_user

def create
  @user = User.create(user_params)

  if @user.save
    session[:user_id] = @user.id
    redirect_to @user, notice: "Thank you for signing up!"
  else
    render 'new'
  end
end