Add ApplicationError type

src/error.rs

@@ -0,0 +1,14 @@
+use std::error::Error;
+
+struct ApplicationError {
+    str: String
+}
+
+impl Error for ApplicationError {
+
+    fn description(&self) -> &str {
+    }
+
+    fn cause(&self) -> Option<&Error> {
+    }
+}