Update answer key and add vector function.

src/koans/vectors.clj

@@ -1,13 +1,16 @@
 (meditations
   "You can use vectors in clojure to create an 'Array' like structure"
-  (= __ (.size (vec nil)))
+  (= __ (.size []))
 
-  "You can create a vector in two ways"
+  "You can create a vector in several ways"
   (= __ (vec nil))
 
   "And populate it in either of these ways"
   (= __ (vec '(1)))
 
+  "There is another way as well"
+  (= __ (vector nil))
+
   "But you can populate it with any number of elements at once"
   (= [1 __] (vec '(1 2)))
 

src/path_to_answer_sheet.clj

@@ -19,8 +19,12 @@
                   "\"No dice!\""
                   "()"]}
    "vectors" {"__" [0
+                    []
+                    [1]
+                    [nil]
                     2
                     [333]
+                    :peanut
                     :jelly
                     :jelly
                     [:butter :and]]}
@@ -35,6 +39,7 @@
                  1
                  1
                  "\"Vancouver\""
+                 nil
                  true
                  false
                  "\"February\""