Ecto first try

create_dweet.exs

defmodule EctoTest.Repo.Migrations.CreateDweet do
  use Ecto.Migration

  def up do
    "CREATE TABLE dweets(id serial primary key, content varchar(140), author varchar(50))" 
  end

  def down do
    "DROP TABLE dweets"
  end
end

dweet.ex

defmodule EctoTest.Dweet do
  use Ecto.Model

  schema "dweets" do
    field :content,        :string
    field :author,         :string
  end
end

mix.exs

defmodule EctoTest.Mixfile do
  use Mix.Project

  def project do
    [app: :ecto_test,
     version: "0.0.1",
     elixir: "~> 0.14.3",
     deps: deps]
  end

  # Configuration for the OTP application
  #
  # Type `mix help compile.app` for more information
  def application do
    [applications: []]
  end

  # Dependencies can be hex.pm packages:
  #
  #   {:mydep, "~> 0.3.0"}
  #
  # Or git/path repositories:
  #
  #   {:mydep, git: "https://github.com/elixir-lang/mydep.git", tag: "0.1"}
  #
  # Type `mix help deps` for more examples and options
  defp deps do
    [
      { :postgrex, "~> 0.5.3" },
      # { :ecto, github: "elixir-lang/ecto" }
      { :ecto, "~> 0.2.2" }
    ]
  end
end

repo.ex

defmodule EctoTest.Repo do
  use Ecto.Repo, adapter: Ecto.Adapters.Postgres

  def url do
    "ecto://postgres:postgres@localhost/ecto_test"
  end

  def priv do
    app_dir(:ecto_test, "priv/repo")
  end

  def conf do
    parse_url "ecto://postgres:postgres@localhost/ecto_test"
  end

end

supervisor.ex

defmodule EctoTest.Supervisor do
  use Supervisor

  def start_link do
    :supervisor.start_link(__MODULE__, [])
  end

  def init([]) do
    children = [
      worker(EctoTest.Repo, [])
    ]

    # See http://elixir-lang.org/docs/stable/Supervisor.Behaviour.html
    # for other strategies and supported options
    supervise(children, strategy: :one_for_one)
  end
end