Use create bang method for version creation on 'create' events so that an exception gets raised when sensible. Fix #207

CHANGELOG.md

@@ -4,6 +4,8 @@
     Fixed compatibility with [ActsAsTaggableOn](https://github.com/mbleigh/acts-as-taggable-on).
   - [#235](https://github.com/airblade/paper_trail/pull/235) - Dropped unnecessary secondary sort on `versions` association.
   - [#212](https://github.com/airblade/paper_trail/pull/212) - Added `PaperTrail::Cleaner` module, useful for discarding draft versions.
+  - [#207](https://github.com/airblade/paper_trail/issues/207) - Versions for `'create'` events are now created with `create!` instead of 
+    `create` so that an exception gets raised if it is appropriate to do so.
   - [#199](https://github.com/airblade/paper_trail/pull/199) - Rails 4 compatibility.
   - [#165](https://github.com/airblade/paper_trail/pull/165) - Namespaced the version class under the `PaperTrail` module.
   

lib/paper_trail/has_paper_trail.rb

@@ -201,8 +201,7 @@ module PaperTrail
           if changed_notably? and version_class.column_names.include?('object_changes')
             data[:object_changes] = PaperTrail.serializer.dump(changes_for_paper_trail)
           end
-
-          send(self.class.versions_association_name).create merge_metadata(data)
+          send(self.class.versions_association_name).create! merge_metadata(data)
         end
       end