chore: Port FreeSewing.dev to docusaurus

The replaces the NextJS site powering FreeSewing.dev with a Docusaurus
setup. It's part of my efforts to simplify FreeSewing's setup so we can
focus on our core value proposition.

sites/dev/docs/tutorials/pattern-design/part2/adding-measurements/readme.mdx

@@ -0,0 +1,68 @@
+---
+title: Adding measurements
+order: 30
+---
+
+FreeSewing is all about _bespoke_ sewing patterns -- or *parametric
+design* to use a more generic term.
+
+That means that when drafting our pattern, I will take the measurements provided
+by the user into account.
+
+Which begs the question, which measurements?
+
+As the pattern designers, you get to decide which measurements are used
+to draft the pattern. For this bib, I am going to use the
+_head circumference_.
+So let's add it as a required measurement.
+
+## Adding required measurements
+
+In our `src/bib.mjs` file, we will add a `measurements` property to the `bib` object.
+This property will be an Array (a list) holding all required measurements for this part.
+
+I am using [*the official name* of the measurement](/reference/measurements) here. For head
+circumference, that name is `head`.
+
+:::note [FIXME]
+The `design/src/bib.mjs` "language" title on the code snippets is out of date. It is used in the tutorial from this point forward to maintain syntax-highlight not yet available for the `src/bib.mjs` title, but should be replaced with `src/bib.mjs`.
+:::
+
+```design/src/bib.mjs
+function draftBib({ part }) {
+  return part
+}
+
+export const bib = {
+  name: 'fromscratch.bib',
+  draft: draftBib,
+  // highlight-start
+  measurements: [ 'head' ],
+  // highlight-end
+}
+```
+
+From now on, this part requires the `head` measurement.
+
+This change will also get picked up by the development environment, which will now complain that it is missing some measurements.
+Since it's just one measurement, I will simply enter a value by hand.
+For example `38` as 38 cm is a realistic head circumference measurement for a baby.
+
+:::tip
+
+##### Why using standard measurements names matters
+
+In principle, I can use any name I want for our measurements.
+The FreeSewing core library does not care.
+
+However, if everybody uses their own (names for) measurements, then people
+aren't able to re-use their measurements across designs.
+
+So if you have any intention at all to play nice with the FreeSewing ecosystem,
+please make sure to re-use the names of existing measurements, rather than
+invent your own.
+
+See the [best practices](/guides/best-practices#reuse-measurements) on this
+topic for details.
+
+:::