tantivy backend: return tags in search results

quickpeep_index/src/backend/tantivy.rs

@@ -202,14 +202,27 @@ impl Backend for TantivyBackend {
             let snippet = article_snippet_generator.snippet(&doc_row.body);
             let excerpt = snippet.to_html();
 
+            let tags = doc
+                .get_all(self.fields.tags)
+                .map(|fv| {
+                    String::from(
+                        *fv.as_facet()
+                            .expect("tags must be facet!")
+                            .to_path()
+                            .last()
+                            .unwrap_or(&""),
+                    )
+                })
+                .collect();
+
             out.push(SearchDocument {
                 score,
                 title: doc_row.title,
                 excerpt,
-                tags: vec![],
+                tags,
                 url: url.to_owned(),
                 favicon_url_hash: doc_row.favicon_url_hash,
-            })
+            });
         }
 
         Ok(out)