Switch to an example that uses Graph instead of GraphMap
diff --git a/src/lib.rs b/src/lib.rs
index b7b3b05..aaaec0c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,35 +12,35 @@
//! # Example
//!
//! ```rust
-//! use petgraph::graphmap::UnGraphMap;
+//! use petgraph::graph::{NodeIndex, UnGraph};
//! use petgraph::algo::{dijkstra, min_spanning_tree};
//! use petgraph::data::FromElements;
//! use petgraph::dot::{Dot, Config};
//!
-//! // Create an undirected graph where nodes are &str, and edges have no weight.
-//! let g = UnGraphMap::<&str, ()>::from_edges(&[
-//! ("a", "b"), ("b", "c"), ("c", "d"),
-//! ("a", "d")]);
+//! // Create an undirected graph with `i32` nodes and edges with `()` associated data.
+//! let g = UnGraph::<i32, ()>::from_edges(&[
+//! (1, 2), (2, 3), (3, 4),
+//! (1, 4)]);
//!
-//! // Find the shortest path from "a" to "d" using 1 as the cost for every edge.
-//! let node_map = dijkstra(&g, "a", Some("d"), |_| 1);
-//! assert_eq!(&1, node_map.get("d").unwrap());
+//! // Find the shortest path from `1` to `4` using `1` as the cost for every edge.
+//! let node_map = dijkstra(&g, 1.into(), Some(4.into()), |_| 1);
+//! assert_eq!(&1i32, node_map.get(&NodeIndex::new(4)).unwrap());
//!
//! // Get the minimum spanning tree of the graph as a new graph, and check that
//! // one edge was trimmed.
-//! let mst = UnGraphMap::from_elements(min_spanning_tree(&g));
-//! assert_eq!(g.all_edges().count() - 1, mst.all_edges().count());
+//! let mst = UnGraph::<_, _>::from_elements(min_spanning_tree(&g));
+//! assert_eq!(g.raw_edges().len() - 1, mst.raw_edges().len());
//!
-//! // Output the tree to graphviz DOT format
+//! // Output the tree to `graphviz` `DOT` format
//! println!("{:?}", Dot::with_config(&mst, &[Config::EdgeNoLabel]));
//! // graph {
-//! // 0 [label="\"a\""]
-//! // 1 [label="\"b\""]
-//! // 2 [label="\"c\""]
-//! // 3 [label="\"d\""]
-//! // 0 -- 1
-//! // 2 -- 3
+//! // 0 [label="\"0\""]
+//! // 1 [label="\"0\""]
+//! // 2 [label="\"0\""]
+//! // 3 [label="\"0\""]
//! // 1 -- 2
+//! // 3 -- 4
+//! // 2 -- 3
//! // }
//! ```
//!
