Add method to create Course from current course

src/courses.rs

@@ -37,6 +37,30 @@ pub struct Meeting {
 }
 
 impl Course {
+    pub fn current() -> Self {
+        Self::from_path(&CONFIG.link_path)
+    }
+
+    // TODO: make this the single method to read a Course
+    pub fn from_path(path: impl AsRef<std::path::Path> + Clone) -> Self {
+        // TODO: make "course.toml" a *documented* magic value or configurable
+        let path: PathBuf = path.as_ref().join("course.toml");
+        let course_string = std::fs::read_to_string(&path);
+        if let Ok(course_string) = course_string {
+            let mut course: Course = toml::from_str(&course_string).unwrap_or_else(|e| {
+                panic!("Error while parsing course at {:?} \n{}", &path, e);
+            });
+            course.path = path;
+            course
+        } else {
+            panic!(
+                "Error while reading course at {:?}\n{}",
+                path,
+                course_string.unwrap_err()
+            );
+        }
+    }
+
     /// Get a reference to the course's semesters.
     pub fn semesters(&self) -> &Vec<String> {
         &self.semesters