sessions_controller.rb

class SessionsController < ApplicationController
  def new
  end

  def create
    user = User.find_by_username(params[:username])
    if user && user.authenticate(params[:password])
        session[:user_id] = user.id
        redirect_to current_user, notice: "Logged in!"
    else
        flash[:error] = "Wrong Username or Password."
        redirect_to root_url
    end
  end

  def destroy
    session[:user_id] = nil
    redirect_to root_url, notice: "Logged out."
	end
end

user_controller.rb

class UsersController < ApplicationController

  def new
		@user = User.new
	end

	def create
  @user = User.new(params[:user])
	  if @user.save
	  	session[:user_id] = @user.id
	    redirect_to @user, notice: "Thanks for joinging Best Scene"
	  else
	    render 'new'
	  end
	end

	def show
  	@user = User.find(params[:id])
	end

	# def self.from_omniauth(auth)
	#   where(auth.slice(:provider, :uid)).first_or_initialize.tap do |user|
	#     user.provider = auth.provider
	#     user.uid = auth.uid
	#     user.name = auth.info.name
	#     user.oauth_token = auth.credentials.token
	#     user.oauth_expires_at = Time.at(auth.credentials.expires_at)
	#     user.save!
 #  	end
	# end

end