Add the function to update an article.

src/main/blog/db.cljs

@@ -111,6 +111,22 @@
       (catch js/Error err (js/console.log (ex-cause err)))))
   channel)
 
+(defn update-article
+  "Update an article and return the id via channel. The timestamp for created will be updated to current timestamp. It gets and returns the same channel."
+  [client {:keys [id title content]} channel]
+  (go
+    (try
+      (let [res (<p! (.query client
+                             (str "update articles "
+                                  "set title = $2,"
+                                      "content = $3,"
+                                      "created = CURRENT_TIMESTAMP "
+                                  "where id = $1;")
+                             (clj->js [id title content])))]
+        (>! channel (-> id)))
+      (catch js/Error err (js/console.log (ex-cause err)))))
+  channel)
+
 (defn delete-article
   "Delete an article and return the id via channel. It gets and returns the same channel."
   [client id channel]