Ruby on Rails - Installing Gemfiles - ruby-on-rails

Question

I am trying to learn Ruby on Rails through this online tutorial
http://ruby.railstutorial.org/ruby-on-rails-tutorial-book
I'm creating an app demo_app for their second chapter.
This is what my gemfile currently looks like
source 'https://rubygems.org'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.0.4'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.2'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 1.2'
group :doc do
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', require: false
end
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'
# Use unicorn as the app server
# gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano', group: :development
# Use debugger
# gem 'debugger', group: [:development, :test]
this is what it's supposed to look like
source 'https://rubygems.org'
ruby '2.0.0'
#ruby-gemset=railstutorial_rails_4_0
gem 'rails', '4.0.4'
group :development do
gem 'sqlite3', '1.3.8'
end
gem 'sass-rails', '4.0.1'
gem 'uglifier', '2.1.1'
gem 'coffee-rails', '4.0.1'
gem 'jquery-rails', '3.0.4'
gem 'turbolinks', '1.1.1'
gem 'jbuilder', '1.0.2'
group :doc do
gem 'sdoc', '0.3.20', require: false
end
group :production do
gem 'pg', '0.15.1'
gem 'rails_12factor', '0.0.2'
end
I don't understand why my gemfile looks so different.
I have the updated versions of rails, ruby and gemfile.
I even ran the commands
bundle install --without production
bundle update
bundle install
and my gemfile still looks like my first snippet of code.
I've been reading through chapters 1 and 2 of this tutorial but can't figure this out. Am I supposed to edit Gemfile in the text editor? I've already tried that and I got a hundred error messages.
How do I install the gemfile so it looks like the code in the second snippet?
Please help

Answer 1

Let's look through the gemfile item by item (Note that any of the numbers after gems are versions and it isn't necessary that your versions match his. You can specify them if you'd feel more comfortable but unless you come to some bug that needs it, you should be fine without.)
source 'https://rubygems.org' - You both have this and this is where the gem, bundle, etc. commands in the console get your gems from for installation.
ruby '2.0.0' - He has this and you don't. What is this doing? It's specifying the version of ruby that he's using in his rails app. You can do this if you want but it won't be necessary unless you've got multiple versions of ruby installed. Perhaps you're using RVM (Ruby Version Manager) in which case this will probably be necessary. Make sure it's the version you have by using ruby -v in the console to check your version. (Output will look something like this: ruby 2.1.1p76 (2014-02-24 revision 45161) [x86_64-darwin13.0] where in the gemfile you can leave everything off besides the 2.1.1
#ruby-gemset=railstutorial_rails_4_0 - This is a comment in his gemfile for his own use. Likely he has multiple gem files and this helps him know which one to use when making the tutorial.
gem 'rails', '4.0.4' - You both have that which is just the version of rails you're using.
Next we have
group :development do
gem 'sqlite3', '1.3.8'
end
This is somewhat different than yours but how come? First of all the group :development do means that we only want to "do" (read: use) the gems in this block when we're in the development group. This one can be more clearly called an environment and can be configured/found in the config/environments/ folder. This is useful for having different gems and settings when running the rails server in development or test or production mode. He has the sqlite3 gem in the development group because he wants to use rails's default database gem for the tutorial. You will notice that you have the sqlite3 gem as well which means you can follow his tutorial successfully.
gem 'sass-rails', '4.0.1'
gem 'uglifier', '2.1.1'
gem 'coffee-rails', '4.0.1'
gem 'jquery-rails', '3.0.4'
gem 'turbolinks', '1.1.1'
gem 'jbuilder', '1.0.2'
You have all these gems in your gemfile as well so no problems there. (They may be with different versions and with comments above them so that you know why each gem is there which is good. Rails puts the comments in by default for clarity in coding.)
group :doc do
gem 'sdoc', '0.3.20', require: false
end
Same as yours and likewise used for the docs group. It means that it won't be used unless you're specifically looking for it.
group :production do
gem 'pg', '0.15.1'
gem 'rails_12factor', '0.0.2'
end
From person experience, I know that these are two gems that are required to deploy an app in production to heroku (a free hosting site) which you'll cover in chapter 1.4. You do not have them because you don't need them until you deploy to heroku. The production group again specifies that you want these gems for when the server runs in production (as it will on heroku). The pg gem is for postgres which is a database alternative to sqlite3 and the rails_12factor is something that enhances 12factor app handling. More can be learned here but it is only necessary to know that heroku requires it to host a rails app.
All the gems in yours that aren't in his and are commented out in yours are old rails standards that are left in because plenty of people still use them and they aren't truly phased out yet. They will not be necessary for the tutorial and you can delete them if you'd like.
Sorry it was long. Hope this helps your understanding.

Answer 2

It looks like your going through Hartl's tutorial, it's a great tutorial, however, if this is your first time coding and or using an MVC framework, everything is going to look like gibberish. Although this is bad practice moving forward, I suggest copying the entire gemfile that Hartl provides into your gemfile and then do a bundle install.
The point of this tutorial for beginners is to get through it with a BASIC understanding of how everything works. It's going to go over a lot of concepts that your not necessarily going to understand or use right away. The best thing to do is power through the best you can and try to finish the app. I finished it in 3 weeks and was more confused than ever, things only started to sync in once I started experimenting on my own and using the tutorial and other ruby/rails docs as a reference.
Programming is hard, and if this is your first foray into application development, I suggest having a basic understanding of Ruby first (http://www.codecademy.com/tracks/ruby) or even learning a scripting language like python (http://www.learnpython.org/). Learning python basics for some odd reason helped me understand ruby better, which made it easier to navigate and understand all the components of rails.
Anyway good luck and stick with it, there are tons of online resources to get you where you need to go. You just have to keep digging.