Next we're going to need to update our rails app to use post press instead of

sequel line.

So we're going to need to first and use the postgres gem.

So I'm going to go here into our apps Gemfile and

you see here a line that says, Use sqlite3 as the database for Active Record.

We wanna use the pg gem instead.

So I'm gonna replace splite3 with pg, and

then we're gonna want a particular version.

So, I'm going to use the so-called twiddle wakka syntax,

which will lock it to a particular minor version.

So, I'm gonna use the latest version that's available

right now 0.18, save that.

And now,

here in the app directory I need to run bundle install to install the new gems.

Next I'm going to need to edit the database.yml file within the config

directory to tell it to connect to postgres instead of sqlite.

So let's delete all these comments here at the top that talk about sqlite and

here in the default set of options we're gonna set the adapter not to sqlite3,

but to postgresql.

It's going to want to know what encoding to save text as.

And we don't want it using ASCII we want it using unicode, so

that we can save characters from other languages.

We'll go and leave the pool config setting, and remove the time out here.

Now let's go on and

edit our particular environments which we'll use the default settings as a basis.

For our development database we want to use not this sqlite database, but

a postgres database named guestbook,

which is the name of our app, underscore development.

Unlike sqlite, postgres supports multiple users updating the same database, so

we need to tell it what username to expect updates to come from.

So I'm gonna add a username, setting and I'll use my developer account name, jay.

We'll do the same for the test environment.

Tell it not to look at a sqlite database file but

a postgres database named guestbook_test.

That's guestbook_test as opposed to guestbook development,

which it was in the development environment.

And again we're going to need a user name setting of jay,

which I'll just copy down from the development environment.

And last up is production,

which again will update it to say guestbook_production.

But for the production environment we don't want to use a username matching our

development name.

We're gonna want the username that's responsible for

maintenance of our application.

That's going to be the deploy user in this case.

Save that and we're done.

So we set our rails app up to use a postgres database ,now

let's actually create that database.

We're going to need to from our app to rectory run the command bin/rails

db:setup and what this will do, is it'll create both the development, and

the test databases, and it will load the schema into them.

Loading the scheme is actually going to be more efficient and safer than actually

running all our migrations since this is a brand new database.

So let's run that command.

It'll create the databases and set up all the tables for us.

Next, let's run the rails server and try the app out, bin/rails server,

go to our browser, and we'll visit localhost:3000, where the app is running.

We've shown an app like this previously,

it's just a simple guestbook app that can collect signatures from your visitors.

The list of signatures is totally blank since this is a new database, so

let's create a signature now.

Hello, PostgresQLI.

And there it is.

And there it is in our list.

Create another one.

And it looks like we're able to write signatures of that base and

read them back out.

We can also view the contents of the postgres database directly.

Just let me quit out of the server here.

And to connect to the database I'm gonna run the command bin/rails db.

This is a command built into rails that takes whatever database you

currently have set up and connects to it using that databases command line program.

So when I run the rails db commanded,

it'll connect me to the postgres terminal program.

From there I can run sequel commands like select * from signatures;

And we're able to see all the records that have been created via the web app.

Only when I exit the postgres terminal we can type backslash q, or

just hold CNTRL+D.

So that's it.

Our app seems to be working with the postgres database in the development

environment.

Next we're gonna show you how to set it up in production.