diff --git a/lib/customUtils.js b/lib/customUtils.js
index af46b07..2a0a40a 100644
--- a/lib/customUtils.js
+++ b/lib/customUtils.js
@@ -21,7 +21,10 @@ function ensureDirectoryExists (dir, cb) {
 
 
 /**
- * Return a random string of length len
+ * Return a random alphanumerical string of length len
+ * There is a very small probability for the length to be less than len
+ * (il the base64 conversion yields to many pluses and slashes) but
+ * that's not an issue here
  */
 function uid (len) {
   return crypto.randomBytes(Math.ceil(len * 5 / 4))
@@ -30,7 +33,6 @@ function uid (len) {
     .slice(0, len);
 }
 
-console.log(uid(5));
 
 
 module.exports.ensureDirectoryExists = ensureDirectoryExists;
diff --git a/lib/datastore.js b/lib/datastore.js
index d569702..d93dd5f 100644
--- a/lib/datastore.js
+++ b/lib/datastore.js
@@ -1,5 +1,7 @@
 /**
  * The datastore itself
+ * TODO
+ * Improve serialization (for types such as Dates, handle new lines in strings)
  */
 
 var fs = require('fs')
@@ -67,9 +69,41 @@ Datastore.treatRawData = function (rawData) {
 };
 
 
+/**
+ * Insert a new document
+ * @param {Function} cb Optional callback, signature: err, insertedDoc
+ */
+Datastore.prototype.insert = function (newDoc, cb) {
+  var callback = cb || function () {}
+    , self = this
+    , persistableNewDoc
+    ;
+
+  try {
+    newDoc._id = customUtils.uid(16);
+    persistableNewDoc = JSON.stringify(newDoc);
+  } catch (e) {
+    return callback(e);
+  }
+
+  fs.appendFile(self.filename, persistableNewDoc + '\n', 'utf8', function (err) {
+    if (err) { return callback(err); }
+
+    var insertedDoc = JSON.parse(persistableNewDoc);
+    self.data.push(insertedDoc);   // Make sure the doc is the same on the disk and in memory
+                                                     // Some docs can't be stringified correctly
+    return callback(null, insertedDoc);
+  });
+};
+
 
 var d = new Datastore('workspace/test.db');
 d.loadDatabase(function (err) {
+  d.insert({ onetest: "oh yeah" }, function (err, insertedDoc) {
+    console.log(err);
+    console.log("===============");
+    console.log(insertedDoc);
+  });
 });