Add solutions to bins

src/cargo_toml.rs

@@ -1,4 +1,5 @@
 use anyhow::{Context, Result};
+use std::path::Path;
 
 use crate::info_file::ExerciseInfo;
 
@@ -40,6 +41,24 @@ pub fn append_bins(
         }
         buf.extend_from_slice(exercise_info.name.as_bytes());
         buf.extend_from_slice(b".rs\" },\n");
+
+        let sol_path = exercise_info.sol_path();
+        if !Path::new(&sol_path).exists() {
+            continue;
+        }
+
+        buf.extend_from_slice(b"  { name = \"");
+        buf.extend_from_slice(exercise_info.name.as_bytes());
+        buf.extend_from_slice(b"_sol");
+        buf.extend_from_slice(b"\", path = \"");
+        buf.extend_from_slice(exercise_path_prefix);
+        buf.extend_from_slice(b"solutions/");
+        if let Some(dir) = &exercise_info.dir {
+            buf.extend_from_slice(dir.as_bytes());
+            buf.push(b'/');
+        }
+        buf.extend_from_slice(exercise_info.name.as_bytes());
+        buf.extend_from_slice(b".rs\" },\n");
     }
 }