Add Run A Basic PostgreSQL Server In Docker as a Docker TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1393 TILs and counting..._
+_1395 TILs and counting..._
 
 ---
 
@@ -194,6 +194,7 @@ _1393 TILs and counting..._
 ### Docker
 
 - [Configure Different Host And Container Ports](docker/configure-different-host-and-container-ports.md)
+- [Run A Basic PostgreSQL Server In Docker](docker/run-a-basic-postgresql-server-in-docker.md)
 
 ### Elixir
 
@@ -1235,6 +1236,7 @@ _1393 TILs and counting..._
 
 ### Tailwind CSS
 
+- [Apply Tailwind Classes To Existing CSS Class](tailwind/apply-tailwind-classes-to-existing-css-class.md)
 - [Base Styles For Text Link](tailwind/base-styles-for-text-link.md)
 - [Specify Paths For Purging Unused CSS](tailwind/specify-paths-for-purging-unused-css.md)
 - [Use Tailwind Typography Prose In Dark Mode](tailwind/use-tailwind-typography-prose-in-dark-mode.md)

docker/run-a-basic-postgresql-server-in-docker.md

@@ -0,0 +1,36 @@
+# Run A Basic PostgreSQL Server In Docker
+
+Here is a basic `docker-compose.yml` file for spinning up a Docker container
+that runs a PostgreSQL server on port 5432. This is what I use to create a
+locally-running PostgreSQL server that lives inside a docker container.
+
+```yaml
+version: "3.7"
+services:
+  postgres:
+    image: postgres:latest
+    restart: always
+    environment:
+      - POSTGRES_USER=postgres
+      - POSTGRES_PASSWORD=postgres
+      - POSTGRES_DB=postgres
+    ports:
+      - "5432:5432"
+    volumes:
+      - ./postgres-data:/var/lib/postgresql/data
+```
+
+To create the docker container and start it up, run the following command from
+the same directory where you put this file:
+
+```bash
+$ docker compose up
+```
+
+This command knows to look for the `docker-compose.yml` file though you can
+always be explicit about the file with the `-f` option.
+
+This configuration points at `postgres:latest` which currently is `16.1`. To
+run a different major version, you can change the `image` to something like
+`postgres:15`. See [Docker Hub](https://hub.docker.com/_/postgres) for more
+options.

tailwind/apply-tailwind-classes-to-existing-css-class.md

@@ -0,0 +1,33 @@
+# Apply Tailwind Classes To Existing CSS Class
+
+Let's say I have some HTML in my app that I don't totally control -- maybe it's
+a 3rd-party component or it was rendered by a markdown transformer. Regardless,
+I am ending up with some HTML where tags have class names that I'd like to
+style.
+
+```html
+<div class="code-block">
+  <!-- ... -->
+</div>
+```
+
+If it was HTML (or JSX) that I was writing, I could stick whatever tailwind
+class names I wanted on the various tags to get the styling just right. But
+since I don't control it directly, I have to find another way to _apply_ those
+tailwind classes.
+
+Enter [tailwind's `@apply`
+directive](https://tailwindcss.com/docs/functions-and-directives#apply). With
+this, I can target an existing class selector with any tailwind utility classes.
+Add lines like the following to your root `tailwind.css` file.
+
+```css
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+/* additional styling here 👇 */
+.code-block {
+  @apply bg-gray-200 rounded-md p-4;
+}
+```