def user=(user)
      session[:user] = nil && return if user.nil?
      session[:user] = store_user(user)
      @user = session[:user] ? user : session[:user]  
    end
def user=(user)
      session[:user] = nil && return if user.nil?
      session[:user] = store_user(user)
      @user = session[:user] ? user : session[:user]  
    end
This method will store the user provided into the session
 and set the user as the currently logged in user
 @return <User Class>|NilClass