Added Rubocop and initial config

app/controllers/sessions_controller.rb

@@ -1,16 +1,19 @@
-class SessionsController < ApplicationController
-  allow_unauthenticated_access only: %i[ new create ]
-  rate_limit to: 10, within: 3.minutes, only: :create, with: -> { redirect_to new_session_url, alert: "Try again later." }
+# frozen_string_literal: true
 
-  def new
-  end
+class SessionsController < ApplicationController
+  allow_unauthenticated_access only: %i[new create]
+  rate_limit to: 10, within: 3.minutes, only: :create, with: lambda {
+    redirect_to new_session_url, alert: 'Try again later.'
+  }
+
+  def new; end
 
   def create
     if user = User.authenticate_by(params.permit(:email_address, :password))
       start_new_session_for user
       redirect_to after_authentication_url
     else
-      redirect_to new_session_path, alert: "Try another email address or password."
+      redirect_to new_session_path, alert: 'Try another email address or password.'
     end
   end