Patch fix crash when using global application

lib/firebase_pushid.ex

@@ -70,9 +70,12 @@ defmodule FirebasePushid do
       [3, 0]
   """
   def increment_list(list) when is_list(list), do: Bump.call(list)
-  def increment_list(data) when is_pid(data)  do
-    new_list = Cache.random_nums(data)
-               |> Bump.call()
+
+  def increment_list(data) when is_pid(data) or data == Cache do
+    new_list =
+      Cache.random_nums(data)
+      |> Bump.call()
+
     Cache.set_random_nums(data, new_list)
   end
 

test/firebase_pushid_test.exs

@@ -4,7 +4,7 @@ defmodule FirebasePushidTest do
   import FirebasePushid
 
   test 'generate' do
-    assert generate
+    assert generate()
   end
 
   test "new_id" do
@@ -21,4 +21,8 @@ defmodule FirebasePushidTest do
     another_id = next_id(data, 1510666856950)
     assert String.slice(another_id, 0..7) != "-Kyukibf"
   end
+
+  test "Multiple calls with FirebasePushid.Cache" do
+    for _ <- 1..100, do: generate()
+  end
 end