Rails Decal Spring 2018 Homework 4

Overview

Welcome to homework 4 of the Rails DeCal! This homework is due Mar 8th at 6:30PM.

We've finally learned about models! At the end of this homework, you will have built an app with the models Cat, Todo, and User with the specifications below (along with their associated tables). As well, you will have created a view to render all the models persisted in your database. Finally, you will have responded to the questions in ANSWERS.md.

As always, remember to bundle install before getting started.

tl;dr: you will build a basic TODO app, an app pretty common in many Rails tutorials.

Application Spec

Models

Cat

name: a string that contains the name of a cat

Todo

tasks: a string name of a Todo that needs to be done
finished: a boolean on whether or not a Todo has been finished

User

username: a string that contains the username of a User
email: a string that contains the email of a User
age: an integer that contains the age of a User

Views

• A home page that renders all Cats, Todos, and Users in your database.
• A form to create new Todos.

Preface

Please briefly examine the repo before you start to see what's been done for you already. The directories app/models and db/migrations are definitely places to look at.

As well, remember to run your migrations with

rails db:migrate

when you want to make changes to your database.

Note that a walkthrough for the homework is included below. For a challenge, try completing the homework without the walkthrough. Essentially, create an application based on the specs we provided above.

Walkthrough

Q1: Cats

One of the first things you should notice is that there is already a migration to create a Cats table with a name field of type string in it, but you don't have a model associated with it yet. Define the model in app/models. Then, create a method called meow (you can call it whatever really) and just have it puts "meow" to the console. Save the file and fire up your Rails console with rails console or rails c; check to see if you can create a new Cat and call its meow method as shown below.

$ rails console
> c = Cat.new
> c.meow # Should print out meow

Q2: Users

For the User model, you'll see a migration - which was made to create a user with a name and an email - and an associated model in app/models. What you need to do is add an integer field called age to our Users table. Check out the Rails documentation for a refresher on how to do this. Run the migration and fire up your Rails console; check to see if your User model now has an age as shown below.

$ rails console
> u = User.new
> u.age # Should not error

Following, try and see if you can rename the column from name to username. You'll find how to do so within the above documentation. Do a similar check to see if it worked.

Q3: Todos

There isn't anything in the repo for todos! This is a perfect chance to see how easy it is to create a migration and model in seconds with by generating the model and migration in one command. Check to see if your changes (namely creating a Todos table and Todo model) worked in Rails console.

Q4: MVC

1. Combining everything you have learned from lectures up to this point, make a home page that displays all the Cats, Todos, and Users in your database.

This will require a controller, a route, and a view. Don't worry about formatting, but feel free to make it pretty if you'd like.

2. Feel free to populate your database by createing some Cats and Users.

3. Make it so that you should be able to go to your homepage simply by visiting localhost:3000.

Hint: How can we retrieve all the objects in our database? The documentation here may help.

Note/Super Hint: There is a lot of flexibility in this question but how we implemented it was to have a Pages controller with home method that initialized the variables @cats, @users, @todos.

Q5: Forms

1. Create a form (form_for) viewable at localhost:3000/todos/new that submits a POST request that will create the a Todo object in your database. Verify this works by visiting your home page and seeing that the object you created shows up.

Hint: This question will require additional controller methods, views, and routes.

Hint: The field for a boolean check box is f.checkbox.

2. You can even have the controller method that creates the Todo object redirect to your home page.

Hint: Use rails routes to see the name of the home page path.

3. (Bonus) Add a link to (look up link_to) your form from the home page.

Q6: Final questions

Answer the questions in ANSWERS.md.

Submission

Run these commands to submit:

git add .
git commit -am "whatever message you want"
git push origin master

Fill out the submission form for this homework, which can be found on Piazza.