Add Set Up A Project-Local Cluster With Postgres.app as a Postgres TIL

postgres/set-up-a-project-local-cluster-with-postgres-app.md

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+# Set Up A Project-Local Cluster With Postgres.app
+
+I want to set up a PostgreSQL cluster in my project directory. This helps
+provide some separation and clarity that this cluster and its databases are just
+for this project.
+
+This can be done with `Postgres.app` (on Mac) hitting the `+` button in the
+bottom left corner of the app. This will pop open a "Create new server" modal.
+
+From there, you'll want to give the server a name that you can identify within
+`Postgres.app`. E.g. "<App Name> Cluster"
+
+Then select the Postgres version. My existing project is still on 17, so I'll
+select that.
+
+The not so intuitive part is the _Data Directory_. Use the "Choose..." file
+picker to find the root directory of your project. Select that. Then click into
+the text input for the data directory and append the name of the data directory
+_to be created_ to that path. If I want it to all go in `postgres-data`, then my
+path will look like:
+
+```
+/Users/me/dev/my-app/postgres-data
+```
+
+The `postgres-data` directory doesn't exist yet. But it will in a moment.
+
+You probably want the default port, so leave that at `5432` unless you know
+otherwise.
+
+Click `Create server`, though that won't actually create the server yet. Now
+with that server selected in `Postgres.app` click the `Initialize` button. That
+will create the `postgres-data` directory and then run `initdb` under the hood
+which will add everything your server needs. It will now be running at that
+port, ready to connect.