Setup Dialyxir and Credo code analyzers:

- Refactor codebase according to analyzers

lib/transport/http.ex

@@ -1,8 +1,13 @@
 defmodule Shortnr.Transport.HTTP do
+  @moduledoc """
+  This module contains functions that can be used to handle HTTP requests and send responses, by
+  manipulating Plug.Conn.
+  """
+
   import Plug.Conn
 
-  @type ok_error :: {:ok, term(), Plug.Conn.t()} | error()
   @type error :: {:error, {atom(), String.t()}, Plug.Conn.t()}
+  @type ok_error :: {:ok, term(), Plug.Conn.t()} | error()
 
   @spec handle(ok_error(), (... -> ok_error())) :: ok_error()
   def handle(error = {:error, _sub_error, _conn}, _func), do: error

lib/transport/json.ex

@@ -1,28 +0,0 @@
-defmodule Shortnr.Transport.Json do
-  import Plug.Conn
-  alias Shortnr.Transport.HTTP
-
-  @spec decode_request(Plug.Conn.t(), module()) :: HTTP.ok_error()
-  def decode_request(conn, struct_module) do
-    {:ok, body, conn} = read_body(conn)
-    {:ok, params} = Jason.decode(body)
-
-    params_list =
-      params
-      |> Map.to_list()
-      |> Enum.map(fn {key, value} -> {String.to_atom(key), value} end)
-
-    {:ok, struct(struct_module, params_list), conn}
-  end
-
-  @spec encode_response(HTTP.ok_error()) :: HTTP.ok_error()
-  def encode_response({:error, {status, response}, conn}) do
-    {:ok, json_body} = Jason.encode(%{data: response})
-    {:error, {status, json_body}, conn}
-  end
-
-  def encode_response({:ok, response, conn}) do
-    {:ok, json_body} = Jason.encode(%{data: response})
-    {:ok, json_body, conn}
-  end
-end

lib/transport/text.ex

@@ -1,4 +1,8 @@
 defmodule Shortnr.Transport.Text do
+  @moduledoc """
+  This modules contains functions to decode and encode text formatted http requests and responses.
+  """
+
   import Plug.Conn
   alias Shortnr.Transport.HTTP
   alias Shortnr.URL

lib/transport/transport.ex

@@ -1,4 +1,7 @@
 defmodule Shortnr.Transport do
+  @moduledoc """
+  This module houses generic Transport types.
+  """
   @type error :: {:error, {atom(), String.t()}}
   @type ok_error :: {:ok, term()} | error()
 end