add a alien target and a shooter to hit it

I am actually really proud that i was able to figure out how to make the alien move
in every direction randomly.

proposal.md/shooter.py

@@ -0,0 +1,48 @@
+
+
+class Shooter:
+    name = "shooter"
+    character = 'I'
+    display = False
+
+    def __init__(self):
+        self.position = (0, 0)
+
+    def handle_keystroke(self, keystroke, game):
+      
+        if keystroke == ' ' and not self.display:
+            ship = game.get_agent_by_name('ship')
+            if ship is None:
+                return
+
+            x, y = ship.position
+            new_position = (x, y - 1)
+
+            if game.on_board(new_position):
+                self.position = new_position
+                self.display = True
+
+    def play_turn(self, game):
+  
+        if not self.display:
+    
+            return
+
+        x, y = self.position
+        new_position = (x, y - 1)
+
+
+        if not game.on_board(new_position):
+            self.display = False
+            return
+
+        agents_by_position = game.get_agents_by_position()
+        agents_here = agents_by_position.get(new_position, [])
+
+        for agent in agents_here:
+            if getattr(agent, "character", None) == 'A':
+                game.end()
+                return
+
+        self.position = new_position
+