trying to fix the docs.rs build :D

Author: angelip2303

Cargo.toml

@@ -15,6 +15,9 @@ categories = ["algorithms", "database", "mathematics", "science"]
 duckdb = { version = "0.7.1" }
 polars = { version = "0.28.0", features = ["lazy"] }
 
+[dev-dependencies]
+duckdb = { version = "0.7.1", features = ["bundled"] }
+
 [package.metadata.docs.rs]
 features = []
 all-features = false

README.md

@@ -48,15 +48,15 @@ https://www.rust-lang.org/tools/install
 project using the Cargo package manager, which is included with Rust. You can
 create a new project by running the following command in your terminal:
 
-```ignore
+```sh
 cargo new my_pregel_project
 ```
 
 3. _Add `pregel-rs` as a dependency_: Next, you need to add `pregel-rs` as a 
 dependency in your `Cargo.toml` file, which is located in the root directory
 of your project. You can add the following line to your `Cargo.toml` file:
 
-```ignore
+```toml
 [dependencies]
 pregel-rs = "0.0.1"
 ```
@@ -69,13 +69,13 @@ functions and use the graph abstraction provided by `pregel-rs` to manipulate th
 can build and run your project using the Cargo package manager. You can build your
 project by running the following command in your terminal:
 
-```ignore
+```sh
 cargo build
 ```
 
 And you can run your project by running the following command:
 
-```ignore
+```sh
 cargo run
 ```
 

src/pregel.rs

@@ -322,18 +322,36 @@ impl PregelBuilder {
     ///
     /// # Examples
     ///
-    /// ```ignore
-    /// let vertices = ...
-    /// let edges = ...
-    ///
-    /// let pregel = PregelBuilder::new(GraphFrame::new(vertices, edges)?)
-    ///     .max_iterations(4)
-    ///     .with_vertex_column(Custom("max_value".to_owned()))
-    ///     .initial_message(col(Custom("value".to_owned()).as_ref()))
-    ///     .send_messages(MessageReceiver::Dst, Pregel::src(Custom("max_value".to_owned())))
-    ///     .aggregate_messages(Pregel::msg(None).max())
-    ///     .v_prog(max_exprs([col(Custom("max_value".to_owned()).as_ref()), Pregel::msg(None)]))
-    ///     .build();
+    /// ```rust
+    /// use polars::prelude::*;
+    /// use pregel_rs::graph_frame::GraphFrame;
+    /// use pregel_rs::pregel::ColumnIdentifier::{Custom, Dst, Id, Src};
+    /// use pregel_rs::pregel::{MessageReceiver, Pregel, PregelBuilder};
+    /// use std::error::Error;
+    ///
+    /// // Simple example of a Pregel algorithm that finds the maximum value in a graph.
+    /// fn main() -> Result<(), Box<dyn Error>> {
+    ///     let edges = df![
+    ///         Src.as_ref() => [0, 1, 1, 2, 2, 3],
+    ///         Dst.as_ref() => [1, 0, 3, 1, 3, 2],
+    ///     ]?;
+    ///
+    ///     let vertices = df![
+    ///         Id.as_ref() => [0, 1, 2, 3],
+    ///         Custom("value".to_owned()).as_ref() => [3, 6, 2, 1],
+    ///     ]?;
+    ///
+    ///     let pregel = PregelBuilder::new(GraphFrame::new(vertices, edges)?)
+    ///         .max_iterations(4)
+    ///         .with_vertex_column(Custom("max_value".to_owned()))
+    ///         .initial_message(col(Custom("value".to_owned()).as_ref()))
+    ///         .send_messages(MessageReceiver::Dst, Pregel::src(Custom("max_value".to_owned())))
+    ///         .aggregate_messages(Pregel::msg(None).max())
+    ///         .v_prog(max_exprs([col(Custom("max_value".to_owned()).as_ref()), Pregel::msg(None)]))
+    ///         .build();
+    ///
+    ///     Ok(println!("{}", pregel.run()?))
+    /// }
     /// ```
     ///
     /// Returns: