feat: execute service as distributed erlang (#96)

To create a cluster with distributed nodes, the following changes were made:

* Use [`dns_cluster`][0] to execute distributed nodes
* Add _script_ to execute distributed nodes locally

Also, improve local execution by:

* Use [`mix release`][1] to make easier [deploy `phoenix`][2]
* Use [`compose watch`][3] to synchronize code from the host with the service

Some minor improvements:

* Ignore files and folders in git and docker
* Remove boilerplate comments

[0]: https://github.com/phoenixframework/dns_cluster
[1]: https://hexdocs.pm/mix/Mix.Tasks.Release.html
[2]: https://hexdocs.pm/phoenix/releases.html
[3]: https://docs.docker.com/compose/how-tos/file-watch/

Co-authored-by: Joao P Dubas <joao.dubas@gmail.com>
Reviewed-on: #96
Co-authored-by: Joao P Dubas <joao.dubas+gitea@gmail.com>
Co-committed-by: Joao P Dubas <joao.dubas+gitea@gmail.com>

lib/wabanex/dev_dns_cluster_resolver.ex

@@ -0,0 +1,26 @@
+defmodule Wabanex.DevDNSClusterResolver do
+  @moduledoc """
+  Local DNS resolver for cluster query.
+  """
+  require Record
+
+  Record.defrecord(:hostent, Record.extract(:hostent, from_lib: "kernel/include/inet.hrl"))
+
+  def basename(node_name) when is_atom(node_name) do
+    [basename, _] = node_name |> to_string() |> String.split("@")
+    basename
+  end
+
+  def connect_node(node_name) when is_atom(node_name) do
+    Node.connect(node_name)
+  end
+
+  def list_nodes, do: Node.list(:visible)
+
+  def lookup(query, type) when is_binary(query) and type in [:a, :aaaa] do
+    case :inet_res.getbyname(~c"#{query}", type) do
+      {:ok, hostent(h_addr_list: addr_list)} -> addr_list
+      {:error, _} -> []
+    end
+  end
+end