feat: Flat import of markdown repo

This is a flat (without history) import of (some of) the content
from our markdown module.

We've imported this without history because the repo contains our
blog posts and showcases posts content prior to porting them to strapi.

Since this contains many images, it would balloon the size of this repo
to import the full history.

Instead, please refer to the history of the (archived) markdown repo
at: https://github.com/freesewing/markdown

markdown/dev/howtos/code/inheritance/en.md

@@ -0,0 +1,52 @@
+---
+title: Design inheritance
+for: developers
+about: Shows how you can use one design as the basis for another
+---
+
+If your pattern is based on, or extending, another pattern (some of) your
+pattern parts will need to be drafted by the parent pattern.
+
+In such a case, rather than return our own draft method for the part, you 
+should instantiate the parent pattern, and return its part draft method:
+
+```js
+import freesewing from "@freesewing/core";
+import Brian from "@freesewing/brian";
+import plugins from "@freesewing/plugin-bundle";
+import config from "../config";
+// Parts
+import draftBack from "./back";
+
+// Create new design
+const Sorcha = new freesewing.Design(config, plugins);
+
+// Attach our own draft method to the prototype
+Sorcha.prototype.draftBack = part => draftBack(part);
+
+// Attach the inherited draft method to the prototype
+Sorcha.prototype.draftBase = function(part) {
+  // Getting the base part from Brian
+  return new Brian(this.settings).draftBase(part);
+};
+```
+
+<Warning>
+
+Because we're using the `this` keyword here, you cannot use the arrow notation.
+
+</Warning>
+
+## Configuration
+
+The inherited pattern parts will use the configuration of your pattern.
+You must take care to make sure that
+your pattern has all the options the parent pattern requires.
+
+For example, if you inherit from a pattern that has a `chestEase` option, you will
+need to add that option to your own patter, because the inherited parts will depend on it.
+
+## Dependencies
+
+When extending a pattern, you should add it as a peer dependency, rather than a regular dependency.
+Doing so will avoid that the parent pattern will get bundled with your own pattern.