Bookmarks in November 2013

29th November 2013 – 1554 words

In this new monthly section, I want to share links that I found interesting. This is a good way, to clean my bookmark list and maybe there are some interesting bits here and there for you as well.

This month was more intense on the Ruby/Rails side and less server stuff. I developed a new website for finding recommended Podcats,, which is very alpha now.

Ruby & Ruby on Rails

Ruby documentation search - Omniref

New, unifying document website for Ruby stdlib, Rails and many Gems.

dickeyxxx : Make bundler crazy fast

Update your bundler, set the environment and speed up your bundle install a lot! Because bundler now will use more than one CPU core.

Rubyists, It's Time to PRY Yourself Off IRB! - SitePoint

For everyone, still not using Pry as an IRB/Rails console replacement, read, learn, apply!

Richard Huang - Upgrade to capistrano3

Capistrano 3 is definitely an improvement IMO. Rails integration with RVM and bundler was very easy.

Errbit: MongoDB is dead. Long live Postgresql

Errbit is an OpenSource error tracking software with Airbrake interface. The main app requires MongoDB, but know somebody made a fork using PostgreSQL instead. Can’t wait to replace our running instance.


Rails-Engine for development which provides a Database structure overview under localhost:3000/rails/info/db where you can browse the table structure and data.

Making uploads work across form redisplays

Found out, carrierwave supports finished uploads on form validation errors! Good to know for the future, no custom Paperclip-sessionID handling required.

Scheduled Jobs · mperham/sidekiq Wiki

I tried out Sidekiq for the background jobs on and love it. Scheduled Jobs is a feature, I want to further explore, like sending E-Mails not instantly, but e.g. on the next workday at daytime and not Sunday in the middle of the night.


Kickstarter is also using Rails for their website. They contributed this Rack middleware for handling various attack scenarios and to rate limit unwanted visitors.

Effortless Two-Factor Authentication

Using Two-factor authentication in your own Rails-app.

RSpec 2.99 and 3.0 betas have been released

Guide to upgrade to Rspec 3. Not sure about the advantages of the new expect syntax.

Coding / General Web development

PostgreSQL: Dont Use CHAR or VARCHAR

This article recommends to just use TEXT as string data type in PostgreSQL, because Chart and Varchar are taking the same space (or more).


Understanding EXPLAIN (ANALYZE) arguments and output of PostgreSQL.


A Mail header, List-Unsubscribe, which should point to a webform for unsubscribing this newsletter. Use it in your (marketing?) e-Mails. Google, AOL, Hotmail will provide a button for the user to unsubscribe when they mark it as spam.

Xpath is actually pretty useful once it stops being confusing

Good overview over Xpath. I generally prefer Css-selector syntax, because the syntax is ubiquitous. But sometimes, like matching content and siblings, Xpath is the only solution.

Devil's Dictionary of Programming

Nice “translation” of various programmer/project manager vocabulary. :)

High Frequency Dating : Mostly Harmless

Hilarious satire about SF startup culture and the urge to automate everything.

The Pastry Box Project

Comprehensive introduction into encodings and how to avoid garbled characters.


Comparison of various large code projects in (estimated) Lines of Code. Impressive!

15 Free APIs You Didn’t Hear About

Various free APIs:

  • Generating Fake User
  • Countries, Timezones, GeoIP
  • file conversion, image information (EXIF)
  • DNS information
  • Weather

Learning & Personal development

Independent Analysis on Supplements & Nutrition |

Website, that give some overview over scientific results of nutritions, like soy, Gluten, eggs and supplements. With TL;DR part!

Theyre Watching You at Work

Very dystopian description of big companies using big data to control and “optimize” employers. Scary.


Find and compare free online courses (MOOC) from Coursera, Udacity, edX and more.

Machine learning

Machine learning is way easier than it looks

Very easy introduction on how to approach machine learning techniques on a Blog for displaying similar articles.

Data mining, forecasting and bioinformatics competitions on Kaggle

Never heard of Kaggle before. Looks interesting, when learning and trying machine learning techniques.

Talk: People who liked this talk also liked ... Building Recommendation...

How to start making recommendations in Ruby. I used some of the ideas for my initial recommendation system on

Machine learning algorithm cheat sheet

Overview over popular classification algorithm and when to use what.

(Android) Apps

Moves App

Promising “Quantified Self” data collection App. Unfortunately, no export function, so a little useless for me.

Orbot: Proxy with Tor

A little late to the party, I just discovered this TOR anonymization App for Android. Using it system wide requires rooting, but can also be used with several Apps out of the box.

Disa Instant Messenger

Disa is an ambitious App that wants to unify the various chat clients. Until it it only can replace WhatsApp and text messages. Curious, to watch that project develop and support Facebook, Gplus, Jabber, WeChat, …:)


Various Vagrant boxes with a lot of different (Linux) distributions and configurations.

Rails meets docker

Getting started with Docker containers and Ruby on Rails.

Beyond Configuration Management

Ansible Blog gives an overview over the vocabulary of Deveops: Configuration Management, Deployment, Provisioning and Orchestration. And how Ansible answer this parts.


a2d3gE: Vim normal mode grammar

Linguistic approach to Vim’s vocabulary: transitive and intransitive verbs :)


Vimrc and dotfiles from Drew Neil - adding various text-objects that I love to use more in the future, like lines.


Sollte ich kostenlos arbeiten?

Einfaches Entscheidungsdiagramm, ob man etwas kostenlos machen sollte.

XING: Ihr Netzwerk in Zahlen

XING’s inviduelle animierte Infografik über das eigene Profil.


How I Ate No Food for 30 Days

VICE magazine reporter tried out the Soylent diet for 30 days.

Deleting Google+ Profile

You can delete your Google+ Profile independently of your “normal” Google profile that you use for log in and Gmail.

What did I miss?