fix Celluloid warnings

Gemfile.lock

@@ -116,23 +116,8 @@ GEM
       activemodel (>= 3.2.0)
       activesupport (>= 3.2.0)
       json (>= 1.7)
-    celluloid (0.17.2)
-      celluloid-essentials
-      celluloid-extras
-      celluloid-fsm
-      celluloid-pool
-      celluloid-supervision
-      timers (>= 4.1.1)
-    celluloid-essentials (0.20.5)
-      timers (>= 4.1.1)
-    celluloid-extras (0.20.5)
-      timers (>= 4.1.1)
-    celluloid-fsm (0.20.5)
-      timers (>= 4.1.1)
-    celluloid-pool (0.20.5)
-      timers (>= 4.1.1)
-    celluloid-supervision (0.20.5)
-      timers (>= 4.1.1)
+    celluloid (0.16.0)
+      timers (~> 4.0.0)
     charlock_holmes (0.7.3)
     chunky_png (1.3.5)
     cliver (0.3.2)
@@ -757,7 +742,7 @@ GEM
     thor (0.19.1)
     thread_safe (0.3.5)
     tilt (1.4.1)
-    timers (4.1.1)
+    timers (4.0.4)
       hitimes
     timfel-krb5-auth (0.8.3)
     tinder (1.10.1)