BTW, do you also have this in your config file?
config :myapp, ecto_repos: [MyApp.Repo]
Additionally, have you tried actually adding the database key?
config :MyApp, MyApp.Repo,
adapter: Ecto.Adapters.Postgres,
pool_size: String.to_integer(System.get_env("POOL_SIZE") || "5"),
ssl: true,
url: System.get_env("DATABASE_URL"),
show_sensitive_data_on_connection_error: true,
+ database: "your_db_name_here"
