add dialyzer and fix id

mix.exs

@@ -9,14 +9,28 @@ defmodule WorkloadService.MixProject do
       elixirc_paths: elixirc_paths(Mix.env()),
       start_permanent: Mix.env() == :prod,
       aliases: aliases(),
-      deps: deps()
+      deps: deps(),
+      dialyzer: [
+        plt_file: {:no_warn, "priv/plts/dialyzer.plt"},
+        plt_add_apps: [:mix, :ex_unit],
+        flags: [
+          # warn on ignored return values
+          :unmatched_returns,
+          # warn on error handling issues
+          :error_handling,
+          # warn when spec is too broad
+          :underspecs,
+          # warn on opaque type violations
+          :no_opaque
+        ]
+      ]
     ]
   end
 
   def application do
     [
       mod: {WorkloadService.Application, []},
-      extra_applications: [:logger, :runtime_tools]
+      extra_applications: [:logger, :runtime_tools, :dialyzer]
     ]
   end
 
@@ -45,7 +59,8 @@ defmodule WorkloadService.MixProject do
       {:amqp, "~> 4.1"},
       {:uuid, "~> 1.1"},
       {:req, "~> 0.5"},
-      {:cors_plug, "~> 3.0"}
+      {:cors_plug, "~> 3.0"},
+      {:dialyxir, "~> 1.4", only: [:dev, :test], runtime: false}
     ]
   end