User sessions and logins - ruby-on-rails

Question

I am trying to implement signup & login features on ROR. on Index page i have created 2 links saying 'new user' and 'login' and in userscontroller i have signup & login methods(updated routes accordingly).
prob: upon clicking new user or login i am getting an error saying
"The action 'show' could not be found for UsersController"
routes.rb:
Rails.application.routes.draw do
resources :users
get 'users/register', :to=>'users#register'
get 'users/signup', :to=>'users#signup'
post 'users/signup', :to=>'users#signup'
post 'users/login', :to=>'users#login'
get 'users/login', :to=>'users#login'
post "users/change_password" => "users#change_password"
get "users/change_password" => "users#change_password"
index.html.erb
<%= link_to "New User", users_register_path %><br>
<%= link_to "Login", users_login_path %><br>
<%= link_to "Change Password", users_change_password_path %><br>
userscontroller:
def index
#user_details = User.all
end
def register
puts "**********************"
puts params
#new_user = User.new
end
def signup
#new_user = User.new(user_register)
if #new_user.save
session[:user] = User.authenticate(#user.name,#user.password)
redirect_to :action=>"welcome"
else
redirect_to :action=>"login"
end
end
def login
puts params
if request.post?
session[:user] = User.authenticate(params[:user][:name], params[:user][:password])
redirect_to :action=>"welcome"
else
# redirect_to :action=>"signup"
end
end
def change_password
puts "**********************"
puts params
puts "**********************"
if request.post?
#pass_change = User.new_password(params[:user][:name], params[:user][:password], params[:user][:new_password])
end
end
def welcome
end
def user_register
params.require(:user).permit(:name,:email,:password,:password_confirmation)
end
end
usermodel.rb:
require 'digest/sha1'
class User < ActiveRecord::Base
attr_accessor :password, :password_confirmation
def password=(pass)
#password = pass
self.salt = User.random_met(10)
self.hashedpassword = User.encrypt(#password, self.salt)
end
def self.encrypt(pass,salt)
Digest::SHA1.hexdigest(pass+salt)
end
def self.authenticate(login, pass)
user_auth = User.find(:first, :conditions=>["login = ?", login])
return nil if user_auth.nil?
return user_auth if User.encrypt(pass,user_auth.salt)==user_auth.hashedpassword
end
def self.new_password(name,old,new)
user = where(:name=>name)
#puts user.email
# how to call setter(password) method from here. because My idea is
#if User.encrypt(old, user.salt)==user.hashedpassword
# run def password=(pass), thereby storing new password.
end
def self.random_met(len)
char = ("a".."z").to_a + ("A".."Z").to_a + ("0".."9").to_a
salted = ""
1.upto(len) { |i| salted << char[rand(char.size-1)] }
return salted
end
end

Answer 1

As written in the Guides,
Rails routes are matched in the order they are specified, so if you
have a resources :photos above a get 'photos/poll' the show action's
route for the resources line will be matched before the get line. To
fix this, move the get line above the resources line so that it is
matched first.
You have defined resources :users above the get routes, so the rails will look for a show route, so is the error.