How to create todo list app in rails, adding, removing and deleting tasks

04 Apr 2014

Posted by Milos Dolobac

In previous part of this tutorial we’ve created static pages

In this post we’ll learn:

  • How to style our app with Bootstrap
  • Showing list of all tasks
  • Adding tasks
  • Deleting Tasks
  • Completing Tasks

Styling our app with Bootstrap

Our app is little bit boring, just html, no css. Let’s do something about that we will use Bootstrap to take care of basic design

Get started with Bootstrap

Bootstrap is a framework for easier developing websites. To use it we have to install bootstrap-sass gem


$ gem 'bootstrap-sass'
$ bundle install

Styling Navigation with Boostrap

Let’s make our navigation prettier. Go to the app/views/layouts and add this code right after body.


          li = link_to "Home", root_path
          li = link_to "Help", help_path
          li = link_to "About", about_path

To work we need to import bootstrap from our extended css file. Create file main.css.scss in app/assets/stylesheets directory.

What is scss

Scss is improved CSS, it allow us to use variables, and removes some repetitions in our commands. If you want to know more about Sass I recommend you pragmatic guide to sass book

Add this code to main.css.scss


@import "bootstrap";

So we have bootstrap imported,let’s look at the home page:

bootstrap navigation

So we’ve applied some styling let’s move on showing list of tasks

Showing list of all tasks

To manipulate tasks we need to create a new controller:

$ rails generate controller Tasks

That’s fine, but we need to record tasks do database. Writing all sql code would be tedious, fortunately there is Active Record to help.

What is Active Record

Active Record is Object-Relation-Mapping Software, that means that maps row in database to Ruby object. You don’t have to write sql, you can use Ruby. If you want to know more about Active Record you can try this site

Creating Models

We need to create models to add records to database.

$ rails generate model Task name:string

Our model isn’t already in database, we need to move our migration. Go to db/migrate folder. You should see migration create_tasks.rb

rails migration

$ rake db:migrate

And move it for test purposes.

$ rake db:test:prepare

Let’s go to rails console and create some tasks.

$ rails console

creating task in console

You saw that we’ve created task with name Pay a bill. That’s fine it works in console, but to view it in browser we need to add some code to our controllers and views.

First we’ll generate list of all tasks. We want to generate lists of tasks on home page, so we’ll use static_pages_controller, otherwise we would use tasks route with tasks controller. Go to app/controllers/static_pages_controller.rb and add this code.


def home
  @tasks = Task.all

This code will check all instances of object Task and save it into variable @tasks

We want to show all tasks on home page, open up app/views/static_pages/home.html.slim and add following code:


  - @tasks.each do |task|
    li =

In this code we connect view with static_pages controller and with each method we loop through all the tasks and add their names to unordered list.

Go to checkout change in browser. You should see list with our recently created tasks.


Adding Tasks

It works, with some problems. Creating task from rails console would be really boring. We need to create task form to do it for us.

First we write up some tests. Create new file tasks.feature


Feature: Task Manipulation
  In order to use my todo list app I want to add, remove and complete my tasks.
    Scenario: Adding task
    When I add a new task
    Then I should see task added message

Now write some step definitions.


When /^I add a new task$/ do
  visit root_path
  fill_in 'task_name', :with => 'Pay a bill'
  expect { click_button "Add task" }.to change(Task, :count).by(1)

We used capybara methods to fill in form for task. fill_in method fills text field task_name and click button with value Add task, then it count number of tasks and if one more tasks has been it will pass.

Try it now. Our tests should fail.

failing form

We need to add routes for tasks. To save the time we use resources to generate all the routes for tasks.


resources :tasks

Let’s try to create our form.


= form_for :task, url: tasks_path do |f|
  = f.label :name
  = f.text_field :name
  = f.submit "Add task", class: "btn btn-large btn-primary"

Maybe you wonder what form_for method does. Take look at this at the browser.

tasks form

If you look at it with Firebug, Chrome Developer Tools or something like that, you should see that form_for method will create html code as you see in the picture.

Form is created but it doesn’t work because we didn’t add controller.


def create
 @task =
 redirect_to root_path

Maybe you wonder what means task_params. Due to security issues Rails developers add some safer code to create new objects.

Add this code to bottom of the tasks_controller


  def task_params

We’ve completed our test let’s move on second. We need to add Task added Message. To display success or error messages with controller we will use flash hash.

Let’s write test first.


Then /^I should see task added message$/ do
  expect(page).to have_content "Task added"

Our test should fail. To work we need to add flash notice to our controller and add it to layout.


flash[:notice] = "Task added"


- if notice
  = notice
- if alert
  = alert

Try to run test now you should see passing tests. If you go to web browser you should see task added message at the top of the page

task added

Removing Tasks

If we’ll complete our tasks we should remove them from tasks list. First we’ll write some tests


When I delete task
Then I should see task deleted message


When /^I delete task$/ do
  visit root_path
  expect { click_button "Delete task" }.to change(Task, :count).by(-1)

Then /^I should see task deleted message$/ do
  expect(page).to have_content("Task deleted")

Our tests should fail. We need to add some code to our views and controllers.

def destroy
  @task = Task.find(params[:id])
  redirect_to root_path
  flash[:alert] = "Task deleted"

This code will find Task by id and saves it to variable and then it will use Active Record destroy method to remove it.

Add this code to home.html.slim


= link_to 'Delete task', task, method: :delete

If you test it right now. You should see passing tests.

Completing Tasks

We want to complete tasks and display it as completed. To do it we need to add boolean completed to our tasks table.

rails generate migration AddCompletedToTask

We need to edit our migration manually. Open up db/migrate/add_completed_to_task.rb and add some content:


def change
  add_column :tasks, :completed, :boolean

We need to add new route.


match 'tasks/complete' => 'tasks#complete' :via => post

And view and controller


= form_tag("/tasks/complete", :method => "post") do
    - @tasks.each do |task|
      - if task.completed == true
          = check_box_tag "tasks_checkbox[]", 
          = link_to 'Delete task', task, method: :delete
      - else
          = check_box_tag "tasks_checkbox[]",
          = link_to 'Delete task', task, method: :delete  

  = submit_tag("Complete Task", class: "btn btn-large btn-primary")    
= form_for :task, url: tasks_path do |f|
  = f.label :name
  = f.text_field :name
  = f.submit "Add task", class: "btn btn-large btn-primary"

We checkout if task has attribute completed set to true and if it does we use strike and little css styling.


def complete
    params[:tasks_checkbox].each do |check|
      task_id = check
      t = Task.find_by_id(task_id)
      t.update_attribute(:completed, true)
      flash[:notice] = "Task completed"
    redirect_to root_path

What’s next

In next tutorial we’ll look at user authentication.

comments powered by Disqus