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/inject/en.md

@@ -0,0 +1,34 @@
+---
+title: Part inheritance
+for: developers
+about: Shows how you can use one part of your pattern as the basis for another
+---
+
+Part inheritance within your own pattern is handled via the `inject` settings in
+the [pattern configuration](/reference/config/). Here is a simple example:
+
+```js
+inject: {
+  front: "base",
+  back: "base",
+
+}
+```
+
+The `front` and `back` parts will be *injected* with the `base` part. As a result, both 
+the `front` and `back` parts will be instantiated with a cloned copy of all the points, paths, 
+and snippets of the `base` part.
+
+This is a common design pattern where one part builds on another. In our example, we can imagine
+a T-shirt pattern where the front and back are rather similar, apart from the neckline.
+So rather than repeating ourselves, we draft a `base` part and inject that in the `front` and 
+`back` parts.
+
+Using `inject` will cause FreeSewing to always draft the injected part prior to 
+drafting the part it gets injected to. It will, in other words, influece the draft order.
+
+<Note>
+
+For inheriting parts from other patterns, please refer to [Design inheritance](/howtos/code/inheritance/).
+
+</Note>