Andrew P. LinchSmyth

Install PostgreSQL on Manjaro

Source: https://wiki.archlinux.org/index.php/PostgreSQL

Install postgresql package sudo pacman -S postgresql
Switch to the postgres user account and initialize the database cluster:

sudo -iu postgres

Realtime Notifications with ActionCable

In this episode we're going to be adding realtime notifications into your app using ActionCable. We've talked about notifications a few times in the past and we used AJAX polling for that. 95% of the time, polling is the solution that would be recommended for it.

But if you're looking for a good introduction into ActionCable then this is a decent one because we're only really using it for one way from the server side to the client side.

Getting started

So to get started we're starting with an app that has Bootstrap installed and then we created a Main controller with an index view which is where we will list our Notifications as for this example.

Before we generate our channels let's install a few things

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

Commit Message Conventions

These rules are adopted from the AngularJS commit conventions.

Goals
Generating CHANGELOG.md
- Recognizing unimportant commits
- Provide more information when browsing the history
Format of the commit message
Subject line

Pry Cheat Sheet

Youtube Tutorial 2013

Command Line

pry -r ./config/app_init_file.rb - load your app into a pry session (look at the file loaded by config.ru)
pry -r ./config/environment.rb - load your rails into a pry session

Debugger

	Алгоритмы:
	1) Стивен Скиена "Алгоритмы. Руководство по разработке"
	2) Томас Кормен "Алгоритмы. Построение и анализ"
	3) Дональд Кнут "Искусство программирования" (никто в реальности не читал этот многотомный труд целиком, но в любой подборке по алгоритмам он обязан быть)

	Общее:
	1) Род Хаггарти "Дискретная математика для программистов"
	2) Керниган, Ритчи "Язык программирования С" - для общего понимания принципов программирования
	3) Дж. Андресон "Дискретная математика и комбинаторика"
	4) Романовский И.В. "Дискретный анализ"

	# Welcome to my "arel gist"!
	## It started hacky, then as an example, but we want it cleaner.

	# ActiveRecord
	## This is an ORM: you call Ruby methods and get Ruby objects, it makes SQL and object instantiations for you.
	## It's Rails' default, but there are alternatives: https://github.com/Sdogruyol/awesome-ruby#orm
	Student.all
	Topic.first
	Workshop.sum(:hours)

	module ArelHelpers
	extend self

	def self.included(base)
	base.extend self
	end

	def asterisk(arel_table_or_model)
	arel_table, columns = case arel_table_or_model
	when Arel::Table

	# This probably isn't a good thing to want to do, but it came up for me,
	# so in the spirit of helping others with weird problems (and because this
	# seems to be documented almost nowhere):

	after_save do

	if some_failing_condition
	errors.add(:something, "some failure happened.")
	raise ActiveRecord::RecordInvalid.new(self)
	end

	# A commented nginx configuration file for Ruby on Rails
	#
	# Author: Tommaso Pavese
	# tommaso@pavese.me
	# http://tommaso.pavese.me
	#
	# License: http://www.wtfpl.net/
	#
	#
	# Tested with: