Add missing cargo pgrx init step to installation instructions

README.md

@@ -23,34 +23,44 @@ For more information on the design of the extension, see the [design document](D
 For more information on PRQL, visit the PRQL [website](https://prql-lang.org/), [repository](https://github.com/PRQL/prql), or [playground](https://prql-lang.org/playground/).
 
 # Intended Use 
-PRQL shines when your SQL queries becomes very long and complex. To convince yourself, take a look at examples on the [PRQL playground](https://prql-lang.org/playground/). You can manage this complexity by porting your most impressive SQL queries to PRQL functions, which can then be used in business logic or other database code. The majority of your database code typically will continue to live in vanilla SQL, ORMs, or other database frameworks.
+PRQL shines when your SQL queries becomes very long and complex. You can manage this complexity by porting your most impressive SQL queries to PRQL functions, which can then be used in business logic or other database code. 
+
+> [!NOTE]
+>
+> PRQL supports `select` statements only. The majority of your database code, including `insert`, `update`, and `delete` statements, will typically continue to live in vanilla SQL, ORMs, or other database frameworks.
 
 # Getting started
-Follow these steps to install PL/PRQL from source: 
+On Ubuntu, follow these steps to install PL/PRQL from source:
 
 1. Install `cargo-pgrx`.
 
     ```cmd
-    cargo install --locked cargo-pgrx
+    cargo install --locked --version=0.11.2 cargo-pgrx
     ```
 
     The version of `cargo-pgrx` must match the version of `pgrx` in `Cargo.toml`. 
 
-2. Clone this repository and `cd` into root directory.
+2. Initialize `pgrx` for your system.
+   ```cmd
+   cargo pgrx init --pg16 <PG16>
+   ```
+   where `<PG16>` is the path to your system installation's `pg_config` tool (typically `/usr/bin/pg_config`). Supported versions are PostgreSQL v12-16. You can also run `cargo pgrx init` and have `pgrx` download, install, and compile PostgreSQL v12-16. These installations are managed by `pgrx` and used for development and testing. Individual `pgrx` installations can be installed using e.g. `cargo pgrx init --pg16 download`. 
+
+3. Clone this repository and `cd` into root directory.
 
     ```cmd
     git clone https://github.com/kaspermarstal/plprql
     cd plprql
     ```
    
-3. Install the extension to the PostgreSQL specified by
+4. Install the extension to the PostgreSQL specified by
    the `pg_config` currently on your `$PATH`.
    ```cmd
    cargo pgrx install --release
    ```
    You can target a specific PostgreSQL installation by providing the path of another `pg_config` using the `-c` flag.
 
-4. Fire up PostgreSQL and start writing functions right away!
+5. Fire up PostgreSQL and start writing functions right away!
    ```cmd
    $ cargo pgrx run pg16
    psql> create extension plprql;
@@ -66,20 +76,14 @@ Follow these steps to install PL/PRQL from source:
    ```
 
 ## Running Tests 
-Run the `init` command:
-
-```cmd
-cargo pgrx init
-```
-
-The `init` command downloads, compiles, and installs PostgreSQL v12-16 which are used for testing. You can now run tests using `cargo pgrx test`. To run tests for all supported versions of PostgreSQL, run
+You can now run tests using `cargo pgrx test`. To run tests for all supported versions of PostgreSQL, run
 
 ```cmd
-cargo pgrx test pg12
-cargo pgrx test pg13
-cargo pgrx test pg14
-cargo pgrx test pg15
 cargo pgrx test pg16
+cargo pgrx test pg15
+cargo pgrx test pg14
+cargo pgrx test pg13
+cargo pgrx test pg12
 ```
 
 # License