fix: adjust model to remove references from things without references

Fixes #69

src/core/base/AcademicDegree.ts

@@ -12,39 +12,46 @@
  * 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} from '../Thing';
-import {SCThingMeta} from '../Thing';
+import {SCThing, SCThingMeta, SCThingWithoutReferences} from '../Thing';
 import {SCMetaTranslations} from '../types/i18n';
 
 /**
  * An academic degree without references
  */
-export interface SCAcademicDegreeWithoutReferences extends SCThing {
+export interface SCAcademicDegreeWithoutReferences
+  extends SCThingWithoutReferences {
   /**
    * The achievable academic degree
    */
   academicDegree: SCGermanAcademicDegree;
 
   /**
-   * The achievable academic degree with academic field specification 
+   * The achievable academic degree with academic field specification
    * (eg. Master of Science)
    */
   academicDegreewithField: string;
 
   /**
-   * The achievable academic degree with academic field specification 
+   * The achievable academic degree with academic field specification
    * shorted (eg. M.Sc.).
    */
   academicDegreewithFieldShort: string;
 }
 
-export interface SCAcademicDegree extends SCAcademicDegreeWithoutReferences {
+/**
+ * An academic degree
+ */
+export interface SCAcademicDegree
+  extends SCAcademicDegreeWithoutReferences, SCThing {
+  // noop
 }
 
 /**
  * Meta information about academic degrees
  */
-export class SCAcademicDegreeMeta extends SCThingMeta implements SCMetaTranslations<SCAcademicDegree> {
+export class SCAcademicDegreeMeta
+  extends SCThingMeta
+  implements SCMetaTranslations<SCAcademicDegree> {
   /**
    * Translations of fields
    */
@@ -86,11 +93,12 @@ export class SCAcademicDegreeMeta extends SCThingMeta implements SCMetaTranslati
 /**
  * Types of (german) academic degrees
  */
-export type SCGermanAcademicDegree = 'bachelor' |
-                                     'diploma' |
-                                     'doctor' |
-                                     'licentiate' |
-                                     'magister' |
-                                     'master' |
-                                     'master pupil' |
-                                     'state examination' ;
+export type SCGermanAcademicDegree =
+  'bachelor'
+  | 'diploma'
+  | 'doctor'
+  | 'licentiate'
+  | 'magister'
+  | 'master'
+  | 'master pupil'
+  | 'state examination' ;