Add customization chapter

Cargo.lock

@@ -61,7 +61,7 @@ dependencies = [
 
 [[package]]
 name = "bat"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
  "ansi_term 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "atty 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",

Cargo.toml

@@ -7,7 +7,7 @@ license = "MIT/Apache-2.0"
 name = "bat"
 readme = "README.md"
 repository = "https://github.com/sharkdp/bat"
-version = "0.1.0"
+version = "0.2.0"
 
 [dependencies]
 atty = "0.2.2"

README.md

@@ -32,3 +32,38 @@ Make sure that you have the devel-version of libopenssl installed (see instructi
 ``` bash
 cargo install bat
 ```
+
+## Customization
+
+`bat` uses the excellent [`syntect`](https://github.com/trishume/syntect/) library for syntax highlighting. `syntect` can read any Sublime Text language definitions and highlighting theme.
+
+To build your own syntax-set and theme, follow these steps:
+
+Create a folder with syntax highlighting theme:
+``` bash
+mkdir -p ~/.config/bat/themes
+cd ~/.config/bat/themes
+
+# Download a theme, for example:
+git clone https://github.com/jonschlinkert/sublime-monokai-extended
+
+# Create a 'Default.tmTheme' link
+ln -s "sublime-monokai-extended/Monokai Extended.tmTheme" Default.tmTheme
+```
+
+Create a folder with language definition files:
+``` bash
+mkdir -p ~/.config/bat/syntax
+cd ~/.config/bat/syntax
+
+# Download some language definition files, for example:
+git clone https://github.com/sublimehq/Packages/
+rm -rf Packages/Markdown
+git clone https://github.com/jonschlinkert/sublime-markdown-extended
+```
+
+Finally, use the following command to parse all these files into a binary
+cache:
+``` bash
+bat init-cache
+```

src/main.rs

@@ -368,7 +368,8 @@ fn run() -> Result<()> {
                 true_color: is_truecolor_terminal(),
             };
 
-            let assets = HighlightingAssets::from_binary();
+            let assets =
+                HighlightingAssets::from_cache().unwrap_or(HighlightingAssets::from_binary());
 
             let theme = assets.theme_set.themes.get("Default").ok_or_else(|| {
                 io::Error::new(