Add the has_member and has_group association helpers to specify model class name

README.md

@@ -74,7 +74,7 @@ Set up your member models:
 ```ruby
 class User
   include Mongoid::Document
-  
+
   groupify :group_member
   groupify :named_group_member
 end
@@ -131,10 +131,44 @@ Example:
 class Organization < Group
   has_members :offices, :equipment
 end
+
+class InternationalOrganization < Organization
+  has_member :offices, class_name: 'CustomOfficeClass'
+  has_member :equipment, class_name: 'CustomEquipmentClass'
+end
 ```
 
 Mongoid works the same way by creating Mongoid relations.
 
+##### Group Associations on Member (ActiveRecord only)
+
+Your member class can be configured to create associations for each expected group type.
+For example, let's say that your member class will have multiple types of organizations as groups.
+The following configuration adds `organizations` and `international_organizations` associations
+on the member model:
+
+```ruby
+class Group < ActiveRecord::Base
+  groupify :group, members: [:users, :assignments], default_members: :users
+end
+
+class Organization < Group
+  has_members :offices, :equipment
+end
+
+class InternationalOrganization < Organization
+end
+
+class Member < ActiveRecord::Base
+  groupify :group_member
+
+  has_group :organizations, class_name: 'Organization'
+  has_group :international_organizations, class_name: 'InternationalOrganization'
+end
+```
+
+Mongoid does not support the `has_group` helper method.
+
 ## Usage
 
 ### Create groups and add members

lib/groupify/adapter/active_record/group.rb

@@ -70,9 +70,22 @@ def member_classes
         # Define which classes are members of this group
         def has_members(*names)
           Array.wrap(names.flatten).each do |name|
+            has_member name
+          end
+        end
+
+        def has_member(name, options = {})
+          klass_name = options[:class_name]
+
+          if klass_name.nil?
             klass = name.to_s.classify.constantize
-            register(klass)
+            association_name = name.is_a?(Symbol) ? name : klass.model_name.plural.to_sym
+          else
+            klass = klass_name.to_s.classify.constantize
+            association_name = name.to_sym
           end
+
+          register(klass, association_name)
         end
 
         # Merge two groups. The members of the source become members of the destination, and the source is destroyed.
@@ -93,10 +106,10 @@ def merge!(source_group, destination_group)
 
         protected
 
-        def register(member_klass)
+        def register(member_klass, association_name = nil)
           (@member_klasses ||= Set.new) << member_klass
 
-          associate_member_class(member_klass)
+          associate_member_class(member_klass, association_name)
 
           member_klass
         end
@@ -135,8 +148,8 @@ def destroy(*args)
           end
         end
 
-        def associate_member_class(member_klass)
-          define_member_association(member_klass)
+        def associate_member_class(member_klass, association_name = nil)
+          define_member_association(member_klass, association_name)
 
           if member_klass == default_member_class
             define_member_association(member_klass, :members)

lib/groupify/adapter/active_record/group_member.rb

@@ -21,11 +21,7 @@ module GroupMember
                    class_name: Groupify.group_membership_class_name
         end
 
-        has_many :groups, ->{ distinct },
-                 through: :group_memberships_as_member,
-                 as: :group,
-                 source_type: @group_class_name,
-                 extend: GroupAssociationExtensions
+        has_group :groups
       end
 
       module GroupAssociationExtensions
@@ -144,6 +140,15 @@ def in_other_groups(*groups)
         def shares_any_group(other)
           in_any_group(other.groups)
         end
+
+        def has_group(name, options = {})
+          has_many name.to_sym, ->{ distinct }, {
+            through: :group_memberships_as_member,
+            source: :group,
+            source_type: @group_class_name,
+            extend: GroupAssociationExtensions
+          }.merge(options.slice :class_name)
+        end
       end
     end
   end

lib/groupify/adapter/mongoid/group.rb

@@ -67,9 +67,22 @@ def member_classes
         # Define which classes are members of this group
         def has_members(*names)
           Array.wrap(names.flatten).each do |name|
+            has_member name
+          end
+        end
+
+        def has_member(name, options = {})
+          klass_name = options[:class_name]
+
+          if klass_name.nil?
             klass = name.to_s.classify.constantize
-            register(klass)
+            association_name = name.is_a?(Symbol) ? name : klass.model_name.plural.to_sym
+          else
+            klass = klass_name.to_s.classify.constantize
+            association_name = name.to_sym
           end
+
+          register(klass, association_name)
         end
 
         # Merge two groups. The members of the source become members of the destination, and the source is destroyed.
@@ -101,9 +114,11 @@ def merge!(source_group, destination_group)
 
         protected
 
-        def register(member_klass)
+        def register(member_klass, association_name = nil)
           (@member_klasses ||= Set.new) << member_klass
-          associate_member_class(member_klass)
+
+          associate_member_class(member_klass, association_name)
+
           member_klass
         end
 
@@ -137,7 +152,7 @@ def delete(*args)
           end
         end
 
-        def associate_member_class(member_klass)
+        def associate_member_class(member_klass, association_name = nil)
           association_name ||= member_klass.model_name.plural.to_sym
 
           has_many association_name, class_name: member_klass.to_s, dependent: :nullify, foreign_key: 'group_ids', extend: MemberAssociationExtensions