start support for songs

def/songs.js

@@ -0,0 +1,24 @@
+class Songs {
+    constructor(info) {
+        if (!info || !info.userid) throw "Can not construct empty profile";
+        this.userid = info.userid;
+        this.data = info.data || {};
+
+        const allowedParams = ["title", 'author', "content", "contentHistory", "bpm", "lang", "reactions", "root", 'beatsPerTempo'];
+        for (const key in info) {
+            if (info.hasOwnProperty(key) && allowedParams.includes(key)) {
+                this[key] = info[key];
+            }
+        }
+        this.createdAt = info.createdAt || new Date();
+        this.lastUpdated = info.lastUpdated || this.createdAt;
+        this.comments = info.comments || [];
+        this.reactions = info.reactions || {};
+    }
+
+    toObj() {
+        return { ...this };
+    }
+}
+
+module.exports = Songs;