Add creature model

models/creature.go

@@ -0,0 +1,6 @@
+package models
+
+// Creature represents the normal creature
+type Creature struct {
+	Coordinate Coordinate
+}

models/zombie.go

@@ -6,13 +6,13 @@ const (
 	minimumValueOnAXis = 0
 )
 
-// Zombie presents a zombie object
+// Zombie represents a zombie object
 type Zombie struct {
 	GridSize   int
 	Coordinate Coordinate
 }
 
-// Coordinate presents the location in the grid of the zombie
+// Coordinate represents the location in the grid of the zombie
 type Coordinate struct {
 	XAxis int
 	YAxis int