fix Time breaking change from crystal 0.27.0

shard.yml

@@ -1,5 +1,5 @@
 name: ulid
-version: 0.1.0
+version: 0.1.1
 
 authors:
   - SuperPaintman <[email protected]>

spec/ulid_spec.cr

@@ -1,5 +1,8 @@
 require "./spec_helper"
 
+
+puts ULID.generate
+
 describe ULID do
   describe ".generate : String" do
     it "should not raise an error" do
@@ -51,7 +54,7 @@ describe ULID do
       1000.times do
         ulid_1 = ULID.generate
         sleep 1.millisecond
-        ulid_2 = ULID.generate(Time.now - 1.second)
+        ulid_2 = ULID.generate(Time.utc - 1.second)
 
         (ulid_2 < ulid_1).should be_true
       end

src/ulid.cr

@@ -5,7 +5,7 @@ module ULID
 
   # Crockford's Base32
   private ENCODING     = "0123456789ABCDEFGHJKMNPQRSTVWXYZ"
-  private ENCODING_LEN = ENCODING.size
+  private ENCODING_LEN = ENCODING.size.as(Int32)
   private TIME_LEN     = 10
   private RANDOM_LEN   = 16
 
@@ -15,17 +15,17 @@ module ULID
   # ULID.generate
   # # => "01B3EAF48P97R8MP9WS6MHDTZ3"
   # ```
-  def generate(seed_time : Time = Time.now) : String
+  def generate(seed_time : Time = Time.utc) : String
     encode_time(seed_time, TIME_LEN) + encode_random(RANDOM_LEN)
   end
 
   private def encode_time(now : Time, len : Int32) : String
-    ms = now.epoch_ms
+    ms = now.to_unix_ms
 
     String.build do |io|
       len.times do |i|
         mod = ms % ENCODING_LEN
-        io << ENCODING[mod]
+        io << ENCODING[mod.to_i]
         ms = (ms - mod) / ENCODING_LEN
       end
     end.reverse