Added db library

libs/Db.js

@@ -0,0 +1,31 @@
+
+class Db {
+  constructor (models) {
+    this.models = models
+  }
+
+  saveSong (value) {
+    // Find if previous song was the same (on bot reload)
+    this.models.Histories
+      .find({})
+      .sort({
+        createdAt: 'desc'
+      })
+      .limit(1)
+      .exec(function (err, last) {
+        if (err ||
+        last.length === 0 ||
+        (last[0] !== undefined &&
+          last[0].artist !== value.artist &&
+          last[0].song !== value.song
+        )
+        ) {
+        // Previous song was different => save song!
+          const history = new this.models.Histories(value)
+          history.save()
+        }
+      })
+  }
+}
+
+module.exports = Db