Let me give you an overview of the components you're going to need to set up your development environment. We'll use the Ruby on Rails framework extensively throughout this specialization, and I'll simply refer to it as Rails. So, more specifically, we'll use Rails to build web applications and to investigate the various technologies and protocols associated with web application frameworks in general. That is, we'll use Rails itself as a tool to explore web application architectures. To use Rails effectively, you'll need the following components. First, you have install the Ruby programming language. Ruby is the programming language that the Rails framework is built on. Packages or libraries in Ruby are referred to as gems. So the Rails framework is actually just a Ruby gem. You're going to need a modern text editor, one that supports syntax highlighting. I'll talk with you more about this shortly. You're going to need a modern web browser, one with integrated developer tools, and I'll show you how to install those on a browser shortly. I'm going to make use of a SQLite Database Browser, again, I'll show you how to get this and install this. And finally, we're going to use Git, which is a distributed version control and source code management system. We'll use this to manage the source code associated with the web applications we develop. And we'll also use it to deploy these applications. You'll use it to submit your programming assignments as well. Again, I'll show you how to use Git shortly. The manner in which you end up configuring your development environment is going to depend upon the operating system you're using as well as your own personal preferences. You have at least three choices, you can roll your own development environment and this is the one that I suggest you try to do. In other words, install all of the components natively on your own machine and manage them yourself. I think this is the best thing for a software engineer to learn how to do. You could also use a virtual machine that comes with Ruby and Rails pre-installed on it. I'll point you to one of those shortly. And the other option is there are some hosted development environments that you can now use. So kind of ironic, this is a web application to develop web applications, these hosted development environments. Let's talk about each of these. But before I do, I want to point you to a website that I think is very helpful. Railsapps.github.io, and you'll see this installing-rails.html. If you go to that site, very detailed instructions on how to install the latest version of Ruby on Rails. So find your operating system on this site and follow the instructions, and that's the best bet and best tip I can give you for helping you to install Ruby on Rails. So let's take a look at a couple of the things on this website. Here's the website that I just mentioned. And notice, if you look through this, it'll explain a little bit about Rails, the current version. And don't worry if this version doesn't match what you're seeing, things change rapidly, as I mentioned. But here, find your operating system, typically it's either going to be Mac OS X or some Mac operating system, Ubuntu. Here, they mention the hosted environments or Windows. Let's take a look first at how you might install this natively. You follow the instructions, so if I pick installing Ruby on Rails for the Mac, I'd click here. And it takes me to the detailed instructions on how to install with this particular operating system. Now, let's look at that second option I mentioned. If you'd like to find a virtual machine, then go to this site called Bitnami and look for the Ruby Stack Virtual Machines, and there's a list of them here. Pick the most current one. So pick the one that has the highest version number. This site only installs the latest stable version, so you should be safe using that. In order to use one of these virtual machines though, first you have to install something that allows you to run that virtual machine. And here's what I recommend using, VirtualBox. This is a product that's offered by Oracle and it's free, and so is the Virtual Machine that I just showed you. So you need to download the particular version that you need for your operating system, install it on your machine, and then this allows you to run another machine on your machine. So it allows you to run a virtual machine. So get VirtualBox, then install Bitnami, and this version has all of the Ruby, Rails, and other dependencies installed and ready to go. Another option that's mentioned in fact on that Rails app site is a hosted development environment, and there's at least two of them. This one's called Cloud9. If you look at the pricing, you should pick this Cloud9 IDE, and there's a free version of this, here it is, that you can select and it gives you one private repository but unlimited public workspaces. Now, this is enough to get you started if you want to start with this. The other one is nitrous.io, N-I-T-R-O-U-S. And if you look at this one, they've got a bunch of different development environments you can install. We want this Rails one. And if you go down to Learn More, you'll see that at the bottom, there's a Rails. If you select this one, this is the one you would need to install in order to have a hosted development environment. So in this case, if you're going to use a hosted development environment, you don't have to install the Ruby on Rails components on your own machine, you're using them in the web. One of the disadvantages of this approach is it's hard to maintain and update if you want to particular gem and it's not available, it may not be possible for you to install it. So again, my recommendation is that you first try to install the development environment on your own from scratch if not a virtual machine. And then the last choice I would make is one of these hosted development environments. Well, throughout this course, I'll demonstrate the manner in which I develop Rails apps using these tools. Your job at this point is to get these running. You need to be able to run Ruby and Rails on your machine. Let me show you what it's going to look like. Open up a command line window for your operating system. On a Mac, if you look under applications and utilities, there's an application called terminal.app, with Linux, there's an application called console. And with Windows, there's the Windows PowerShell that you would use. If you type ruby -v, you'll see the version of Ruby that's installed on your machine. If you don't see anything, then it may not be properly installed. And don't worry if this version number does not match what is on your machine. Same for Rails. If you type rails -v, then you should hopefully see a version number pop up with the version of Rails that's installed on your machine. Your job is to try and make these things work on your machine at this point.