Add scheduler structure

src/kernel/scheduler.rs

@@ -0,0 +1,32 @@
+use crate::utility::list::List;
+use crate::kernel::thread::Thread;
+use std::rc::Rc;
+
+
+struct Scheduler<> {
+    ready_list: List<Rc<Thread>>
+}
+
+impl Scheduler {
+
+    /// Constructor
+    /// 
+    /// Initilize the list of ready thread
+    pub fn new() -> Self {
+        Self {
+            ready_list: List::new()
+        }
+    }
+
+    /// Mark a thread as aready, but not necessarily running yet.
+    /// 
+    /// Put it in the ready list, for later scheduling onto the CPU.
+    /// 
+    /// ## Pamameter
+    /// 
+    /// **thread**: Thread is the thread to be put on the read list
+    pub fn ready_to_run(&mut self, thread: Rc<Thread>) {
+        self.ready_list.push_back(thread);
+    }
+    
+}