Fix custom join_table name on habtm reflections

When used a custom join_table name on a habtm, rails was not saving it
on Reflections. This causes a problem when rails loads fixtures, because
it uses the reflections to set database with fixtures.

activerecord/CHANGELOG.md

@@ -1,3 +1,11 @@
+*   When using a custom `join_table` name on a `habtm`, rails was not saving it
+    on Reflections. This causes a problem when rails loads fixtures, because it
+    uses the reflections to set database with fixtures.
+
+    Fixes #14845.
+
+    *Kassio Borges*
+
 *   Reset the cache when modifying a Relation with cached Arel.
     Additionally display a warning message to make the user aware.
 

activerecord/lib/active_record/associations.rb

@@ -1590,7 +1590,7 @@ def destroy_associations
         hm_options[:through] = middle_reflection.name
         hm_options[:source] = join_model.right_reflection.name
 
-        [:before_add, :after_add, :before_remove, :after_remove, :autosave, :validate].each do |k|
+        [:before_add, :after_add, :before_remove, :after_remove, :autosave, :validate, :join_table].each do |k|
           hm_options[k] = options[k] if options.key? k
         end
 

activerecord/lib/active_record/associations/builder/has_many.rb

@@ -5,7 +5,7 @@ def macro
     end
 
     def valid_options
-      super + [:primary_key, :dependent, :as, :through, :source, :source_type, :inverse_of, :counter_cache]
+      super + [:primary_key, :dependent, :as, :through, :source, :source_type, :inverse_of, :counter_cache, :join_table]
     end
 
     def self.valid_dependent_options

activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb

@@ -21,6 +21,7 @@
 require 'models/sponsor'
 require 'models/country'
 require 'models/treaty'
+require 'models/vertex'
 require 'active_support/core_ext/string/conversions'
 
 class ProjectWithAfterCreateHook < ActiveRecord::Base
@@ -819,4 +820,8 @@ def test_association_with_validate_false_does_not_run_associated_validation_call
     assert_equal 1, treasure.rich_people.size
     assert_equal person_first_name, rich_person.first_name, 'should not run associated person validation on update when validate: false'
   end
+
+  def test_custom_join_table
+    assert_equal 'edges', Vertex.reflect_on_association(:sources).join_table
+  end
 end