Update Cargo.toml on dev check

src/dev/check.rs

@@ -1,5 +1,16 @@
-use anyhow::Result;
+use std::fs;
 
-pub fn check() -> Result<()> {
-    todo!()
+use anyhow::{Context, Result};
+
+use crate::{info_file::InfoFile, init::cargo_toml};
+
+pub fn check(info_file: InfoFile) -> Result<()> {
+    // TODO: Add checks
+
+    fs::write("Cargo.toml", cargo_toml(&info_file.exercises))
+        .context("Failed to update the file `Cargo.toml`")?;
+
+    println!("Everything looks fine!");
+
+    Ok(())
 }