chore: change to ordered_set for improved performance

Author: heywhy

lib/elasticlunr/core/index.ex

@@ -41,7 +41,7 @@ defmodule Elasticlunr.Index do
 
     name = Keyword.get_lazy(opts, :name, &UUID.uuid4/0)
     db_name = String.to_atom("elasticlunr_#{name}")
-    db = DB.init(db_name, ~w[set public]a)
+    db = DB.init(db_name, ~w[ordered_set public]a)
 
     id_field = Field.new(db: db, name: ref, pipeline: Pipeline.new([IdPipeline]))
     fields = Map.put(%{}, to_string(ref), id_field)

test/serializer_test.exs

@@ -8,7 +8,7 @@ defmodule Elasticlunr.SerializerTest do
 
     structure = [
       "settings#name:index|ref:id|pipeline:",
-      "db#name:elasticlunr_index|options:compressed,named_table,set,public",
+      "db#name:elasticlunr_index|options:compressed,named_table,ordered_set,public",
       "field#name:id|pipeline:Elixir.Elasticlunr.Index.IdPipeline|store_documents:false|store_positions:false"
     ]
 
@@ -25,7 +25,7 @@ defmodule Elasticlunr.SerializerTest do
 
     structure = [
       "settings#name:index|ref:id|pipeline:",
-      "db#name:elasticlunr_index|options:compressed,named_table,set,public",
+      "db#name:elasticlunr_index|options:compressed,named_table,ordered_set,public",
       "field#name:body|pipeline:|store_documents:true|store_positions:true",
       "field#name:id|pipeline:Elixir.Elasticlunr.Index.IdPipeline|store_documents:false|store_positions:false"
     ]