How to configure Elixir Mix project with Ecto SQLite3?

Alright, that’s good. What’s the rest of your mix.exs file (and why do you have :ecto_sqlite3 as extra_application?

And do you have Eelarve.Repo defined somewhere?

E.g. taken from this guide

defmodule Eelarve.Repo do
  use Ecto.Repo,
    otp_app: :eelarve,
    adapter: Ecto.Adapters.SQLite3
end