diff --git a/lib/realtime.js b/lib/realtime.js
index a3c56c4..2139060 100644
--- a/lib/realtime.js
+++ b/lib/realtime.js
@@ -652,17 +652,25 @@ function operationCallback(socket, operation) {
         if (!user) return;
         userId = socket.request.user.id;
         if (!note.authors[userId]) {
-            models.Author.create({
-                noteId: noteId,
-                userId: userId,
-                color: user.color
-            }).then(function (author) {
-                note.authors[author.userId] = {
-                    userid: author.userId,
-                    color: author.color,
-                    photo: user.photo,
-                    name: user.name
-                };
+            models.Author.findOrCreate({
+                where: {
+                    noteId: noteId,
+                    userId: userId
+                },
+                defaults: {
+                    noteId: noteId,
+                    userId: userId,
+                    color: user.color
+                }
+            }).spread(function (author, created) {
+                if (author) {
+                    note.authors[author.userId] = {
+                        userid: author.userId,
+                        color: author.color,
+                        photo: user.photo,
+                        name: user.name
+                    };
+                }
             }).catch(function (err) {
                 return logger.error('operation callback failed: ' + err);
             });