Check for unapplied migrations on startup

Closes #1328

test/repo_test.exs

@@ -4,7 +4,10 @@
 
 defmodule Pleroma.RepoTest do
   use Pleroma.DataCase
+  import ExUnit.CaptureLog
   import Pleroma.Factory
+  import Mock
+
   alias Pleroma.User
 
   describe "find_resource/1" do
@@ -46,4 +49,44 @@ defmodule Pleroma.RepoTest do
       assert Repo.get_assoc(token, :user) == {:error, :not_found}
     end
   end
+
+  describe "check_migrations_applied!" do
+    setup_with_mocks([
+      {Ecto.Migrator, [],
+       [
+         with_repo: fn repo, fun -> passthrough([repo, fun]) end,
+         migrations: fn Pleroma.Repo ->
+           [
+             {:up, 20_191_128_153_944, "fix_missing_following_count"},
+             {:up, 20_191_203_043_610, "create_report_notes"},
+             {:down, 20_191_220_174_645, "add_scopes_to_pleroma_feo_auth_records"}
+           ]
+         end
+       ]}
+    ]) do
+      :ok
+    end
+
+    test "raises if it detects unapplied migrations" do
+      assert_raise Pleroma.Repo.UnappliedMigrationsError, fn ->
+        capture_log(&Repo.check_migrations_applied!/0)
+      end
+    end
+
+    test "doesn't do anything if disabled" do
+      disable_migration_check =
+        Pleroma.Config.get([:i_am_aware_this_may_cause_data_loss, :disable_migration_check])
+
+      Pleroma.Config.put([:i_am_aware_this_may_cause_data_loss, :disable_migration_check], true)
+
+      on_exit(fn ->
+        Pleroma.Config.put(
+          [:i_am_aware_this_may_cause_data_loss, :disable_migration_check],
+          disable_migration_check
+        )
+      end)
+
+      assert :ok == Repo.check_migrations_applied!()
+    end
+  end
 end