add 'draw_line' method

src/drawing.rs

@@ -9,7 +9,8 @@ pub fn draw_circle(center: Point, radius: f64, context: &web_sys::CanvasRenderin
     .unwrap();
 }
 
-/*
 pub fn draw_line(p1: Point, p2: Point, context: &web_sys::CanvasRenderingContext2d) {
+  context.move_to(p1.0, p1.1);
+  context
+    .line_to(p2.0, p2.1);
 }
-*/

src/lib.rs

@@ -25,5 +25,8 @@ pub fn start() {
   drawing::draw_circle(Point(75.0, 75.0), 35.0, &context);
   drawing::draw_circle(Point(60.0, 65.0), 5.0, &context);
 
+  drawing::draw_line(Point(0.0, 0.0), Point(150.0, 150.0), &context);
+  drawing::draw_line(Point(0.0, 150.0), Point(150.0, 0.0), &context);
+
   context.stroke();
 }