todo_app.rb

require 'sinatra'
require 'data_mapper'

DataMapper.setup(:default, ENV['DATABASE_URL'] || "sqlite3://#{Dir.pwd}/development.db")

class Tarefa
  include DataMapper::Resource

  property :id,           Serial
  property :title,        String, :required => true
  property :details,      String
  property :completed,    Boolean
end

DataMapper.finalize.auto_upgrade!

get '/' do
  @tarefas = Tarefa.all
  erb :index
end

post '/' do
  Tarefa.create params[:tarefa]
  redirect to('/')
end

get '/tarefas/:id' do |id|
  @tarefa = Tarefa.get!(id)
  erb :'tarefas/show'
end

get '/tarefas/:id/edit' do |id|
  @tarefa = Tarefa.get!(id)
  erb :'tarefas/edit'
end

put '/tarefas/:id' do |id|
  tarefa = Tarefa.get!(id)
  success = tarefa.update!(params[:tarefa])

  if success
    redirect "/tarefas/#{id}"
  else
    redirect "/tarefas/#{id}/edit"
  end
end

delete '/tarefas/:id' do |id|
  tarefa = Tarefa.get!(id)
  tarefa.destroy!
  redirect "/"
end