added sortedSetIncrBy

src/database/level/sorted.js

@@ -292,4 +292,8 @@ module.exports = function(db, module) {
 			callback(null, returnData);
 		});
 	}
+
+	module.sortedSetIncrBy = function(key, increment, value, callback) {
+		throw new Error('not implemented');
+	};
 };

src/database/mongo/sorted.js

@@ -410,4 +410,18 @@ module.exports = function(db, module) {
 			callback(null, data);
 		});
 	}
+
+	module.sortedSetIncrBy = function(key, increment, value, callback) {
+		callback = callback || helpers.noop;
+		if (!key) {
+			return callback();
+		}
+		var data = {};
+		value = helpers.fieldToString(value);
+		data['score'] = parseInt(increment, 10);
+
+		db.collection('objects').findAndModify({_key: key, value: value}, {}, {$inc: data}, {new:true, upsert:true}, function(err, result) {
+			callback(err, result ? result[value] : null);
+		});
+	};
 };

src/database/redis/sorted.js

@@ -211,4 +211,8 @@ module.exports = function(redisClient, module) {
 			callback(err, results ? results[1] : null);
 		});
 	}
+
+	module.sortedSetIncrBy = function(key, increment, value, callback) {
+		redisClient.zincrby(key, increment, value, callback);
+	};
 };