docs: Create publishing chapter (#407)

* Create

* Mention example and link to optimizing docs

* remove extra quotes

* Update publishing.md

* Update publishing.md

* add converting note

* Update publishing.md

* Update publishing.md

* Update publishing.md

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Co-authored-by: Marc Espin <[email protected]>

Author: tigerros

book/src/SUMMARY.md

@@ -21,5 +21,4 @@
 - [Animating](./guides/animating.md)
 - [Virtualizing](./guides/virtualizing.md)
 - [Devtools](./guides/devtools.md)
-- [Publishing]()
-
+- [Publishing](./guides/publishing.md)

book/src/guides/publishing.md

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+# Publishing
+
+> ⚠️ Before publishing, you should consider removing insecure metadata.
+> For example, images might have EXIF location data in them.
+
+**Freya** produces a self-contained executable in `target/release`, so you can technically distribute that.
+However, you might want to create an installer instead. You can use executable packagers of your choice, but
+for a more automated and "Rusty" version, you can use [**cargo-packager**](https://github.com/crabnebula-dev/cargo-packager), which is basically an abstraction
+over executable packagers, which you would have to set up yourself.
+
+There is an [example](https://github.com/marc2332/freya/tree/main/examples/installer) you can check out.
+
+## `cargo-packager` installation
+
+Run:
+
+```
+cargo install cargo-packager --locked
+```
+
+## Usage
+
+Add this to your `Cargo.toml`:
+
+```
+[package.metadata.packager]
+before-packaging-command = "cargo build --release" # Before packaging, packager will run this command.
+product-name = "My App" # By default, the crate name will be shown, but you probably prefer "My App" over "my-app".
+```
+
+And run:
+
+```
+cargo packager --release
+```
+
+And there you go! You should now have an installer in `target/release` for your current OS.
+To publish your app on a different OS, see the next section, [Configuration](#configuration).
+
+## Configuration
+
+We used a very bare-bones example, so make sure to check out all configuration options in the [Config struct](https://docs.rs/cargo-packager/latest/cargo_packager/config/struct.Config.html)
+in the `cargo-packager` API docs. Note that underscores should be hyphens when you use TOML.
+
+One crucial configuration field is `formats`.
+This is a list of installers that `cargo-packager` should generate, and by default, it's your current OS.
+You can have a look at the list on [GitHub](https://github.com/crabnebula-dev/cargo-packager#supported-packages), or on the [API docs](https://docs.rs/cargo-packager/latest/cargo_packager/config/enum.PackageFormat.html).
+
+### Changing the executable icon on Windows
+
+`cargo-packager` will change the icon for platforms other than Windows using the [`icons`](https://docs.rs/cargo-packager/latest/cargo_packager/config/struct.Config.html#structfield.icons)
+field, but it does not do it on Windows (yet?).
+
+Anyway, the `cargo-packager` team recommends using [`winresource`](https://crates.io/crates/winresource)
+(as opposed to [`winres`](https://crates.io/crates/winres) which is not maintained).
+Before using it, make sure that you have the requirements that are listed on its page.
+
+Add it to your build dependencies in `Cargo.toml`:
+
+```toml
+[build-dependencies]
+winresource = "0.1.7"
+```
+
+And add this to your `build.rs` file (make sure you link it in your `Cargo.toml`):
+
+```rs
+// Change this to your icon's location
+const ICON: &str = "assets/icons/icon.ico";
+
+fn main() {
+    if std::env::var("CARGO_CFG_TARGET_OS").unwrap() == "windows" {
+        let mut res = winresource::WindowsResource::new();
+        res.set_icon(ICON);
+        res.compile().unwrap();
+    }
+}
+```
+
+To convert more common formats like `.png` or `.jpg` to an `.ico`, you can use [imagemagick](https://imagemagick.org).
+Once installed, run `magick convert your_icon.png icon.ico`.
+
+# Optimizing
+
+The ["Optimizing" chapter](https://dioxuslabs.com/learn/0.4/cookbook/optimizing) in the Dioxus docs applies in Freya too.
+Note that WebAssembly-related tips are irrelevant.