Node revamp: Using PostgreSQL lesson

[fcasibu]

Because

To add a new lesson about Using PostgreSQL for the node revamp.

This PR

• Adds new lesson to nodeJS/express/using_psql.md
• Copied text from Installing PostgreSQL in the RoR section and intro from our mongodb lesson with just a slight adjustment
• Disable lint issue for heading (should we fix it here? and maybe open a new PR for the ruby one?)

Issue

Closes #27643

Additional Information

Pull Request Requirements

• I have thoroughly read and understand The Odin Project curriculum contributing guide
• The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• If any lesson files are included in this PR, they follow the Layout Style Guide

[MaoShizhong]

@thatblindgeye I remember you saying something before about how the current way of doing dropdowns isn't fully accessible, and there may be a way to make them so and resolve heading duplication without needing to disable the rules. Is this something that could be actioned on with relative ease in the respective repos? Or is this something more involved that we should disable the rules for now still?

[01zulfi]

@fcasibu 🔥 🔥 great stuff, can't wait to see Postgres stuff out

I have thoughts on how to best teach the lesson content. I presumed that the lesson overview I wrote on the issue would suffice, but after reading the lesson, it needs more "hand-holdiness" i.e. more detailed code-along instructions.

Here's what I propose:

We'll be creating a simple "add user to db" application. Have learners set up a simple express app with the following routes:

• GET / to display list of all users
• GET '/new-user` to display form with one "user name" input. this forms sends a request to
• POST /new-user

Now, we'll instruct to install pg.

Now, we have to create a database, we'll instruct learners to do that in the psql shell:

• run psql in the cli
• run create database top_users; in the shell
• then \l top_users then \c top_users
• then create table top_users ( ... ) in the shell
• then the insert query

The shell experience will be invaluable to leaners.

Then set up following files and also provide code. Ask learners to log the functions to see if they get expected data:

• db/pool.js exports the pool object
• db/queries.js exports two functions getAllUsers and createUser

Finally, ask learners to use these functions in their controllers.

Once their app is functioning, now we can introduce a "populatedb" script. We'll ask them to delete the database and use this script to setup the db instead of shell.

[01zulfi]

closed in favor of #27960