Added note on psycopg2 installation error

Author: chriscarrollsmith

docs/installation.qmd

@@ -61,6 +61,8 @@ pipx install poetry
 poetry install
 ```
 
+(Note: if `psycopg2` installation fails with a `ChefBuildError`, you just need to install the PostgreSQL headers first and then try again.)
+
 3.  Activate shell
 
 ``` bash

index.qmd

@@ -87,6 +87,8 @@ pipx install poetry
 poetry install
 ```
 
+(Note: if `psycopg2` installation fails with a `ChefBuildError`, you just need to install the PostgreSQL headers first and then try again.)
+
 3.  Activate shell
 
 ``` bash
@@ -97,7 +99,7 @@ poetry shell
 
 ### Set environment variables
 
-Copy .env.example to .env with `cp .env.example .env`.
+Copy `.env.example` to `.env` with `cp .env.example .env`.
 
 Generate a 256 bit secret key with `openssl rand -base64 32` and paste it into the .env file.