use Mix.Config
# ...
config :ecto_101_migrations_schemas, Ecto101MigrationsSchemas.Repo,
  adapter: Ecto.Adapters.Postgres,
  database: "ecto_test",
  username: "postgres",
  password: "",
  hostname: "localhost"

config :ecto_101_migrations_schemas, ecto_repos: [Ecto101MigrationsSchemas.Repo]