fix: adjust model to remove references from things without references

Fixes #69

src/core/base/ThingThatCanBeOffered.ts

@@ -12,7 +12,7 @@
  * You should have received a copy of the GNU General Public License along with
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
-import {SCThing, SCThingTranslatableProperties} from '../Thing';
+import {SCThing, SCThingTranslatableProperties, SCThingWithoutReferences} from '../Thing';
 import {SCOrganizationWithoutReferences} from '../things/Organization';
 import {SCPersonWithoutReferences} from '../things/Person';
 import {SCTranslations} from '../types/i18n';
@@ -32,7 +32,8 @@ export interface SCPriceGroup {
 /**
  * Price distinctions for academic context
  */
-export interface SCAcademicPriceGroup extends SCPriceGroup {
+export interface SCAcademicPriceGroup
+  extends SCPriceGroup {
   /**
    * Price for employees
    */
@@ -52,7 +53,8 @@ export interface SCAcademicPriceGroup extends SCPriceGroup {
 /**
  * A thing without references that can be offered
  */
-export interface SCThingThatCanBeOfferedWithoutReferences extends SCThing {
+export interface SCThingThatCanBeOfferedWithoutReferences
+  extends SCThingWithoutReferences {
   /**
    * Translations of a thing that can be offered
    */
@@ -63,11 +65,16 @@ export interface SCThingThatCanBeOfferedWithoutReferences extends SCThing {
  * A thing that can be offered
  */
 export interface SCThingThatCanBeOffered<T extends SCPriceGroup>
-  extends SCThing {
+  extends SCThing, SCThingThatCanBeOfferedWithoutReferences {
   /**
    * List of offers for that thing
    */
   offers?: Array<SCThingThatCanBeOfferedOffer<T>>;
+
+  /**
+   * Translations of a thing that can be offered
+   */
+  translations?: SCTranslations<SCThingThatCanBeOfferedTranslatableProperties>;
 }
 
 /**