add Dockerfile technical reference

src/development/intro.md

@@ -43,3 +43,52 @@ scoop install mask
 
 A maskfile is self-documenting, because it is written in Markdown. You can view
 the maskfile [here](https://github.com/rustic-rs/rustic/blob/main/maskfile.md).
+
+## Dockerfile technical reference
+
+We utilize multistage docker build with following stages
+
+- `chef` - utility step to shorten code
+- `planner` - analyze the current project to determine the minimum subset of
+  files (`Cargo.lock` and `Cargo.toml` manifests) required to build it
+- `builder` - consists of 2 container layers
+  - first - contains build dependencies (it wii be rebuild only if Cargo.lock or
+    Cargo.toml has changes)
+  - second - main build of our application
+- `runtime` - debian slim image for running our app (we don't use alpine cause
+  [this](https://web.archive.org/web/20231214004214/https://andygrove.io/2020/05/why-musl-extremely-slow/))
+
+### `cargo-chef`
+
+We utilize `chef` to cache the dependencies of Rust project and speed up Docker
+builds.
+
+#### Installation
+
+Locally
+
+```bash
+cargo install cargo-chef --locked
+```
+
+Dockerfile
+
+```bash
+FROM lukemathwalker/cargo-chef:latest-rust-1.70.0 AS chef
+```
+
+#### Usage
+
+In Dockerfile we used `ARG` to lock `rust` version. (By default = `1.70.0`).
+
+When `rust` version is updated, you need to either update the standard version
+
+```bash
+ARG RUST_VERSION=1.70.0
+```
+
+or use the build argument
+
+```bash
+docker build --build-arg="RUST_VERSION=1.70.0" .
+```