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CREATE EXTENSION btree_gist;

CREATE TABLE room_reservations (
    room_id integer,
    reserved_at timestamptz,
    reserved_until timestamptz,
    canceled boolean DEFAULT false,
    EXCLUDE USING gist (
        room_id WITH =, tstzrange(reserved_at, reserved_until) WITH &&
    ) WHERE (not canceled)

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collapsible markdown?

CLICK ME

yes, even hidden code blocks!

print("hello world!")

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Install a new ruby version with chruby

OSX

First of all you must update ruby-build to update definitions list.

brew update

And update ruby-build

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#!/bin/bash

# --------------------------------------------------------------------------------------------
# Installs Ruby 2.6 using rbenv/ruby-build on the Raspberry Pi (Raspbian)
#
# Run from the web:
#   bash <(curl -s https://gist.githubusercontent.com/blacktm/8302741/raw/install_ruby_rpi.sh)
# --------------------------------------------------------------------------------------------

# Welcome message

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// Run the file `node simple_and_fake_jasmine_describe_it_expect_equalsto_pattern.js` from containing folder.
// Should receive 1 passing and 1 failing test (as noted by text color -> Green/Red).
// To understand: read from the call site and work backwards.

// -- Fancy console printing like tests do (no emojis yet) -- //
const printToConsole = function(text, status = 'normal', padding = false) {
  const CC = {
    Reset: '\x1b[0m',
    Underscore: '\x1b[4m',
    FgRed: '\x1b[31m',

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// A super simple no-edge case version of the `expect` function 
// as seen in mocha/jasmine test environments.

// Long form

// step one: define a function called `expect` which takes one value. 
// This value is intended to be the return value of a function.
const expect = function(actualValue) {
  // assign a property onto `expect` called 'equalsTo' which is 
  // itself  a function taking one argument (using `this` keyword 

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# change foo to your library name
# change Foo::Database to your Sequel database

namespace :bundler do
  task :setup do
    require 'rubygems'
    require 'bundler/setup'
  end
end

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def floatify_string?(val)
  # if its already a number type, return it
  return val if (val.class == Integer || val.class == Float)

  # pre-match zero so that we can initially weed out all no-numeric strings as unparseable
  return 0.0 if val == "0" || val == "0.0"
  return nil if val.to_f == 0.0 # "Hello".to_f => 0.0

  # only match float-like looking values: "1.0" => 1.0, "1" => 1.0, "0.001" => 0.001, "01345345" => 1345345.0
  return val.to_f if val =~ /^[-+]?[0-9]*\.?[0-9]+$/

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hash = { 'foo' => 'bar' }

# Version 1
hash = Hash[hash.map { |k, v| [k.to_sym, v] }]

# Version 2
hash = hash.reduce({}) do |memo, (k, v)| 
  memo.tap { |m| m[k.to_sym] = v }
end

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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