Fix migrations: run after Repo starts, not before

lib/microwaveprop/application.ex

@@ -7,8 +7,6 @@ defmodule Microwaveprop.Application do
 
   @impl true
   def start(_type, _args) do
-    migrate()
-
     children = [
       MicrowavepropWeb.Telemetry,
       Microwaveprop.Repo,
@@ -24,6 +22,9 @@ defmodule Microwaveprop.Application do
     opts = [strategy: :one_for_one, name: Microwaveprop.Supervisor]
     result = Supervisor.start_link(children, opts)
 
+    # Run migrations after Repo is started
+    Microwaveprop.Release.migrate()
+
     # Load ML model in dev/test only (Nx/Axon not compiled for prod)
     if Application.get_env(:microwaveprop, :load_ml_model, false) do
       Microwaveprop.Propagation.load_ml_model()
@@ -32,12 +33,6 @@ defmodule Microwaveprop.Application do
     result
   end
 
-  # Tell Phoenix to update the endpoint configuration
-  # whenever the application is updated.
-  defp migrate do
-    Microwaveprop.Release.migrate()
-  end
-
   @impl true
   def config_change(changed, _new, removed) do
     MicrowavepropWeb.Endpoint.config_change(changed, removed)