Add unlogged option for extended database support

Some postgres-compatible databases such as Yugabyte don't support
unlogged tables. Making oban_peers unlogged isn't a requirement for Oban
to operate, so it can be disabled with a migration flag.

lib/oban/migration.ex

@@ -153,6 +153,10 @@ defmodule Oban.Migration do
   Run migrations in an alternate prefix but don't try to create the schema:
 
       Oban.Migration.up(prefix: "payments", create_schema: false)
+
+  Disable `UNLOGGED` tables for databases that don't support it (e.g. Yugabyte)
+
+      Oban.Migration.up(unlogged: false)
   """
   def up(opts \\ []) when is_list(opts) do
     migrator().up(opts)

lib/oban/migrations/postgres.ex

@@ -89,8 +89,9 @@ defmodule Oban.Migrations.Postgres do
     opts = Enum.into(opts, %{prefix: @default_prefix, version: version})
 
     opts
+    |> Map.put(:quoted_prefix, inspect(opts.prefix))
+    |> Map.put(:escaped_prefix, String.replace(opts.prefix, "'", "\\'"))
+    |> Map.put_new(:unlogged, true)
     |> Map.put_new(:create_schema, opts.prefix != @default_prefix)
-    |> Map.put_new(:quoted_prefix, inspect(opts.prefix))
-    |> Map.put_new(:escaped_prefix, String.replace(opts.prefix, "'", "\\'"))
   end
 end

lib/oban/migrations/postgres/v11.ex

@@ -3,15 +3,17 @@ defmodule Oban.Migrations.Postgres.V11 do
 
   use Ecto.Migration
 
-  def up(%{prefix: prefix, quoted_prefix: quoted}) do
+  def up(%{prefix: prefix, quoted_prefix: quoted, unlogged: unlogged?}) do
     create_if_not_exists table(:oban_peers, primary_key: false, prefix: prefix) do
       add :name, :text, null: false, primary_key: true
       add :node, :text, null: false
       add :started_at, :utc_datetime_usec, null: false
       add :expires_at, :utc_datetime_usec, null: false
     end
 
-    execute "ALTER TABLE #{quoted}.oban_peers SET UNLOGGED"
+    if unlogged? do
+      execute "ALTER TABLE #{quoted}.oban_peers SET UNLOGGED"
+    end
   end
 
   def down(%{prefix: prefix}) do