Added example to README.md

README.md

@@ -4,3 +4,16 @@ and access to various registers.
 
 Memory addresses `0xA0000 -> 0xBFFFF` must be readable and writeable
 this crate to work properly.
+
+## Usage
+```rust
+use vga::colors::{Color16Bit, TextModeColor};
+use vga::Text80x25;
+
+let text_mode = Text80x25::new();
+let color = TextModeColor::new(Color16Bit::Yellow, Color16Bit::Black);
+
+text_mode.set_mode();
+text_mode.clear_screen();
+text_mode.write_character(0, 0, b'H', color);
+```