Compatability with Rails 5.2's ActiveModel::Dirty

* We're now expected to call `#reset_changes`, rather than manipulating `@changed_attributes` directly.
* `ActiveRecord::Dirty` now assumes that any object it's included in which has an `@attributes` instance variable is database-backed, and has very specific API requirements for `@attributes` (must be an array of  `ActiveModel::Attribute` instances). This conflicts with modis' `@attributes`, so we trivially renamed this to `@modis_attributes` to distinguish them.

.travis.yml

@@ -20,9 +20,6 @@ gemfile:
   - gemfiles/rails_51.gemfile
   - gemfiles/rails_52.gemfile
 
-allow_failures:
-  - gemfile: gemfiles/rails_52.gemfile
-
 env:
   global:
     secure: LrTz0Pq2ibNZuKDhdzcrvEUSNxUpPopEq9aJeCxy3UpV0v4vpHBtWV0S6zofvf98g/RkZ6cGI1u+0H578dHgE6pWTo+iR8LAwqPKofrFIWRkeo+M77Vs5swahb3mQyPOcig1hfVWDm25MsojePYm70eBIcBU55NWImtdePXfiU0=

lib/modis/attribute.rb

@@ -19,8 +19,6 @@ def self.included(base)
 
     module ClassMethods
       def bootstrap_attributes(parent = nil)
-        attr_reader :attributes
-
         class << self
           attr_accessor :attributes, :attributes_with_defaults
         end
@@ -73,6 +71,10 @@ def #{name}=(value)
       end
     end
 
+    def attributes
+      @modis_attributes
+    end
+
     def assign_attributes(hash)
       hash.each do |k, v|
         setter = "#{k}="
@@ -96,12 +98,8 @@ def set_sti_type
       write_attribute(:type, self.class.name)
     end
 
-    def reset_changes
-      @changed_attributes = nil
-    end
-
     def apply_defaults
-      @attributes = Hash[self.class.attributes_with_defaults]
+      @modis_attributes = Hash[self.class.attributes_with_defaults]
     end
   end
 end

lib/modis/model.rb

@@ -35,7 +35,7 @@ def initialize(record = nil, options = {})
       apply_defaults
       set_sti_type
       assign_attributes(record) if record
-      reset_changes
+      changes_applied
 
       return unless options.key?(:new_record)
 

lib/modis/persistence.rb

@@ -180,7 +180,7 @@ def create_or_update(args = {})
       future = persist
 
       if future && (future == :unchanged || future.value == 'OK')
-        reset_changes
+        changes_applied
         @new_record = false
         true
       else

modis.gemspec

@@ -18,8 +18,8 @@ Gem::Specification.new do |gem|
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.require_paths = ["lib"]
 
-  gem.add_runtime_dependency 'activemodel', ['>= 3.0', '< 5.2']
-  gem.add_runtime_dependency 'activesupport', ['>= 3.0', '< 5.2']
+  gem.add_runtime_dependency 'activemodel', ['>= 3.0']
+  gem.add_runtime_dependency 'activesupport', ['>= 3.0']
   gem.add_runtime_dependency 'redis', '>= 3.0'
   gem.add_runtime_dependency 'hiredis', '>= 0.5'
   gem.add_runtime_dependency 'connection_pool', '>= 2'