routing issue passing id rails 4 - ruby-on-rails-4

Question

Firstly apologies as just when i think i have a grip on routing i find that i don't!!
When a registered user logs in to my app they are taken to the admin index view and all i am trying to do is display their user name within that view.
This is my routes config: -
Easygifts::Application.routes.draw do
get 'admin' => 'admin#index'
controller :sessions do
get 'login' => :new
post 'login' => :create
delete 'logout' => :destroy
end
get "sessions/create"
get "sessions/destroy"
resources :users
resources :admin
resources :stores do
collection do
get "writing"
get "office"
get "time"
get "home"
get "wellness"
get "travel"
get "bags"
get "leisure"
get "contact"
get "terms"
end
member do
get 'quote'
end
end
resources :products
Users login via the sessions controller and are passed on to the Admin controllers index view. Where i am trying to display their name using the following: - <th colspan="2">Welcome <%= #users.name %></th>
The Sessions controller: -
class SessionsController < ApplicationController
skip_before_action :authorize
def new
end
def create
user = User.find_by(name: params[:name])
if user and user.authenticate(params[:password])
session[:user_id] = user.id
redirect_to admin_url
else
redirect_to login_url, alert: "Invalid user/password combination"
end
end
def destroy
session[:user_id] = nil
redirect_to stores_url, notice: "Logged out"
end
end
The Users Controller: -
class UsersController < ApplicationController
before_action :set_user, only: [:show, :edit, :update, :destroy]
# GET /users
# GET /users.json
def index
#users = User.order(:name)
end
# GET /users/1
# GET /users/1.json
def show
end
# GET /users/new
def new
#user = User.new
end
# GET /users/1/edit
def edit
end
# POST /users
# POST /users.json
def create
#user = User.new(user_params)
respond_to do |format|
if #user.save
format.html { redirect_to users_url, notice: "User #{#user.name} was successfully created." }
format.json { render action: 'show', status: :created, location: #user }
else
format.html { render action: 'new' }
format.json { render json: #user.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /users/1
# PATCH/PUT /users/1.json
def update
respond_to do |format|
if #user.update(user_params)
format.html { redirect_to users_url, notice: "User #{#user.name} was successfully updated." }
format.json { head :no_content }
else
format.html { render action: 'edit' }
format.json { render json: #user.errors, status: :unprocessable_entity }
end
end
end
# DELETE /users/1
# DELETE /users/1.json
def destroy
begin
#user.destroy
flash[:notice] = "User #{#user.name} deleted"
rescue StandardError => e
flash[:notice] = e.message
end
respond_to do |format|
format.html { redirect_to users_url }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_user
#user = User.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def user_params
params.require(:user).permit(:name, :password, :password_confirmation, :add1, :add2, :add3, :add4, :post_code, :home_tel, :mobile, :ice_tel, :ni_number, :position, :image_url, :staff_num, :start_date, :birthday)
end
end
And the Admin Controller: -
class AdminController < ApplicationController
def index
#users = User.find(params[:id])
end
end
My first point of confusion is whether i should be going through the Sessions controller or the Users controller?
If it's in the Sessions controller am i supposed to write something like get 'admin#index' => :show
Or if it's in Users am i to write something like resources :users do member do get 'admin' end end
I think i have to define a controller with an action within my routes but i don't understand in this instance how to work out who is doing what.