App walkthrough

• On > assets > images > javascripts > stylesheets are part of the Rails assets pipeline, which means that Rails is going to generate all this for un on deployment. 
• The controllers contains the application controller (core controller). For the most part, all of the other controllers are going to inherit from the application controller. 
• Inherit means that they get all the different methods from the application controller. (sign: < )
• If we want any piece of behavior in our app, we have to add it in our application controller. 
• Each particular piece of code that we generate will get its own helper
• If we want something, a certain piece of behavior to apply to all of our different views, we will put that in the application helper

For the most part, helpers are going to be used to generate code for our views. While, controller code would be used to generate behavior for our controllers.

• > app > models > concerns: contain shared behavior between models 
• <%= --> this is calling a helper or evaluating some sort of code and then displaying the results.
• It it doesn't include an = sign, the output of the code will not be there.
• Bin directory: contains different functions 
• Config directory > routes: is where we tell our application were different parts go 
• Config > database.yml file: Contains our database configuration for each environment
• Config > application.rb: Contains specific configuration code for our application. 
• Locales directory: Contains translation information. If we wanted to translate our application into another language, the translation keys are here 
• Lib directory: Contains different library code for our app. 
• Public directory: 404, 422, 500 pages