Added a basic solution based on level-sublevel.

problems/queue/setup.js

@@ -0,0 +1,7 @@
+
+function setup(run, callback) {
+  console.log(arguments)
+}
+
+module.exports       = setup
+module.exports.async = true

problems/queue/solution.js

@@ -0,0 +1,45 @@
+var sublevel = require('level-sublevel')
+
+function Queue(db, name) {
+  if (!(this instanceof Queue)) return new Queue(db, name)
+
+  this._db = sublevel(db).sublevel(name)
+}
+
+module.exports = Queue
+
+Queue.prototype.push = function(element, callback) {
+  var key = (new Date()).toISOString()
+
+  this._db.put(key, element, callback)
+
+  return this;
+}
+
+Queue.prototype.shift = function(callback) {
+  var stream = this._db.createReadStream({
+                 limit: 1
+               })
+
+    , db = this._db
+
+  stream.once('data', function(data) {
+    db.del(data.key, function(err) {
+      callback(err, data.value)
+    })
+  })
+
+  stream.once('error', callback)
+
+  return this;
+}
+
+Queue.prototype.clear = function(callback) {
+  this._db.createReadStream()
+      .pipe(this._db.createWriteStream({
+              type: 'del'
+            }))
+      .on('close', callback)
+
+  return this;
+}