has_many: support chaining where clauses

Modify the `ActiveResource::Associations` module's `has_many` definition
to invoke `Base.all`, rather than `Base.find(:all)` in order to utilize
the deferred record fetching introduced in [#422][].

```ruby
class Person < ActiveResource::Base
  self.site = "https://example.com"

  has_many :people
end

person = Person.find(1)                 # => GET /people/1.json
person.people                           # => GET /people.json?person_id=1
person.people.where(name: "Related")    # => GET /people.json?person_id=1&name=Related
```

[#422]: #422

Author: seanpdoyle

lib/active_resource/associations.rb

@@ -148,7 +148,7 @@ def defines_has_many_finder_method(reflection)
       elsif attributes.include?(method_name)
         attributes[method_name]
       elsif !new_record?
-        instance_variable_set(ivar_name, reflection.klass.find(:all, params: { "#{self.class.element_name}_id": self.id }))
+        instance_variable_set(ivar_name, reflection.klass.all(params: { "#{self.class.element_name}_id": self.id }))
       else
         instance_variable_set(ivar_name, self.class.collection_parser.new)
       end

test/cases/association_test.rb

@@ -39,6 +39,24 @@ def test_association_class_build
   def test_has_many
     External::Person.send(:has_many, :people)
     assert_equal 1, External::Person.reflections.select { |name, reflection| reflection.macro.eql?(:has_many) }.count
+
+    ActiveResource::HttpMock.respond_to.get "/people.json?person_id=1", {}, { people: [{ id: 2, name: "Related" }] }.to_json
+    person = External::Person.new({ id: 1 }, true)
+
+    people = person.people
+
+    assert_equal [ "Related" ], people.map(&:name)
+  end
+
+  def test_has_many_chain
+    External::Person.send(:has_many, :people)
+
+    ActiveResource::HttpMock.respond_to.get "/people.json?name=Related&person_id=1", {}, { people: [{ id: 2, name: "Related" }] }.to_json
+    person = External::Person.new({ id: 1 }, true)
+
+    people = person.people.where(name: "Related")
+
+    assert_equal [ "Related" ], people.map(&:name)
   end
 
   def test_has_many_on_new_record