Update build scripts

Signed-off-by: Oliver Davies <oliver@oliverdavies.uk>

nix-for-php-developers/build

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+NAME="$(basename "$PWD")"
+
+out="out"
+
+mkdir -p "$out"
+
+marp slides.md \
+  --allow-local-files \
+  --pdf
+
+echo ""
+
+mv -v slides.pdf "$out/$NAME.pdf"

nix-for-php-developers/clean

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+rm -vfr out

nix-for-php-developers/watch

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+marp slides.md --preview --watch "$@"