Bug 35197: Field name consistency

This patch adds a to_api_mapping and updates the yaml definitions to be
ensure we are consistent with modern best practice for our api field
names.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>

Koha/AdditionalField.pm

@@ -42,6 +42,23 @@ sub effective_authorised_value_category {
     return $category;
 }
 
+=head3 to_api_mapping
+
+This method returns the mapping for representing an AdditionalField object
+on the API.
+
+=cut
+
+sub to_api_mapping {
+    return {
+        id                        => 'additional_field_id',
+        tablename                 => 'table_name',
+        authorised_value_category => 'authorised_value_category_name',
+        marcfield                 => 'marc_field',
+        marcfield_mode            => 'marc_field_mode'
+    };
+}
+
 sub _type { 'AdditionalField' }
 
 =head1 AUTHOR

api/v1/swagger/definitions/additional_field.yaml

@@ -1,26 +1,26 @@
 ---
 type: object
 properties:
-  id:
+  additional_field_id:
     type: integer
     description: internally assigned additional field identifier
     readOnly: true
-  tablename:
+  table_name:
     description: name of the table this additional field corresponds to
     type: string
   name:
     description: name of the additional field
     type: string
-  authorised_value_category:
+  authorised_value_category_name:
     description: authorised value category of the additional field
     type:
       - string
       - "null"
-  marcfield:
-    description: marcfield of the additional field
+  marc_field:
+    description: marc field of the additional field
     type: string
-  marcfield_mode:
-    description: marcfield mode of the additional field
+  marc_field_mode:
+    description: marc field mode of the additional field
     type: string
     enum:
       - get
@@ -31,5 +31,5 @@ properties:
 
 additionalProperties: false
 required:
-  - id
-  - tablename
+  - additional_field_id
+  - table_name