Application myapp_core exited: MyappCore.Application.start(:normal, []) returned an error: shutdown: failed to start child: MyapCore.Repo

Hello, I’m deploying the phoenix appliocation on Google Cloud Platform. I’m using following versions:
elixir:1.9.4
phoenix: 1.4.1
phoenix_ecto:4.0
ecto_sql:3.0
myxql:0.3.0

I’m containerizing it using docker and getting following error:

Application myapp_core exited: MyappCore.Application.start(:normal, []) returned an error: shutdown: failed to start child: MyappCore.Repo
    ** (EXIT) an exception was raised:
        ** (FunctionClauseError) no function clause matching in Code.ensure_loaded?/1
            (elixir) lib/code.ex:1044: Code.ensure_loaded?(10)
            (ecto_sql) lib/ecto/adapters/sql.ex:478: Ecto.Adapters.SQL.normalize_pool/1
            (elixir) lib/keyword.ex:873: Keyword.update/4
            (elixir) lib/keyword.ex:877: Keyword.update/4
            (ecto_sql) lib/ecto/adapters/sql.ex:456: Ecto.Adapters.SQL.init/3
            (ecto) lib/ecto/repo/supervisor.ex:162: Ecto.Repo.Supervisor.init/1
            (stdlib) supervisor.erl:295: :supervisor.init/1
            (stdlib) gen_server.erl:374: :gen_server.init_it/2
** (Mix) Could not start application myapp_core: MyappCore.Application.start(:normal, []) returned an error: shutdown: failed to start child: MyappCore.Repo
    ** (EXIT) an exception was raised:
        ** (FunctionClauseError) no function clause matching in Code.ensure_loaded?/1
            (elixir) lib/code.ex:1044: Code.ensure_loaded?(10)
            (ecto_sql) lib/ecto/adapters/sql.ex:478: Ecto.Adapters.SQL.normalize_pool/1
            (elixir) lib/keyword.ex:873: Keyword.update/4
            (elixir) lib/keyword.ex:877: Keyword.update/4
            (ecto_sql) lib/ecto/adapters/sql.ex:456: Ecto.Adapters.SQL.init/3
            (ecto) lib/ecto/repo/supervisor.ex:162: Ecto.Repo.Supervisor.init/1
            (stdlib) supervisor.erl:295: :supervisor.init/1
            (stdlib) gen_server.erl:374: :gen_server.init_it/2