Creating activity feeds in PostgreSQL 9.5

Piotr Okoński – May 18th, 2016 – PostgreSQL, databases
In this post I explain how to create modern activity feeds with Facebook-like grouping using only PostgreSQL.

Upgrading PostgreSQL from 9.4 to 9.5 on Ubuntu 15.10

Piotr Okoński – February 8th, 2016 – PostgreSQL, Ubuntu, databases

Now that PostgreSQL 9.5 came out with even more awesome features, it’s time to upgrade!

Since upgrading from 9.4 might be a bit of a hassle if we used official Ubuntu repositories before, I decided to write a short guide to help with the process.

Running concurrent workflows in Ruby

Maciej Nowak – February 1st, 2016 – Ruby, background jobs, concurrency, Sidekiq

Have you ever struggled with a chain of rake tasks that needed to be run periodically and their runtime was giving you a headache? Did you ask yourself how to save time by boosting execution along with readability for huge chunks of jobs? These questions...

Creating a BitTorrent client in Haskell #3

Jakub Okoński – November 24th, 2015 – Haskell, BitTorrent

In the previous post, I laid down foundations for PeerMonad, where most of the protocol logic will live. This article will focus on using that towards our goal – downloading files.

Role-based authorization in Rails

Piotr Okoński – November 13th, 2015 – Ruby, Rails, Authorization, Access Granted, CanCan
A dive into creating permission system based on roles using Access Granted and how it compares to already established solutions, such as CanCan.

Creating a BitTorrent client in Haskell #2

Jakub Okoński – October 13th, 2015 – Haskell, BitTorrent

In the previous post, I went over the protocols and file formats required for the BitTorrent protocol. This article will focus on laying down a strong foundation for our future efforts.

Creating a BitTorrent client in Haskell #1

Jakub Okoński – October 5th, 2015 – Haskell, BitTorrent

This is the first post in a series on writing a BitTorrent client in Haskell.

Generating quines in Ruby

Mateusz Lenik – October 1st, 2015 – Ruby, Quines

Quines are a very interesting concept in computing as they are self-replicating programs.

Let us start with describing what exactly is a quine – it is a program that prints its own source code, usually to the standard output. It has to store its source code in itself (it cannot rely on the source file laying around on the file system).

For example, this program matches the first requirement, but it does not match the second.


The simplest quine in Ruby is an empty program, but I would call that cheating since there is no program at all.