Added a working solution for task1 and ran the tests

hw2/task1/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "task1"
+version = "0.1.0"
+authors = ["Lorenz Bung <lorenz.bung@googlemail.com>"]
+
+[dependencies]

hw2/task1/src/lib.rs

@@ -0,0 +1,19 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}
+pub fn hamming_distance(s1: &str, s2: &str) -> Result<usize, String> {
+    if s1.len() != s2.len() {
+        return Err("Strings must be of equal length!".to_string());
+    }
+    let mut dist: usize = 0;
+    for i in 0..s1.len() {
+        if s1.chars().nth(i) != s2.chars().nth(i) {
+            dist += 1
+        }
+    }
+    Ok(dist)
+}