diff --git a/lib/tasks/emoji.rake b/lib/tasks/emoji.rake
index 6ea15b77f34..b559d73fed5 100644
--- a/lib/tasks/emoji.rake
+++ b/lib/tasks/emoji.rake
@@ -1,8 +1,8 @@
-EMOJI_LIST_URL = "http://unicode.org/emoji/charts/full-emoji-list.html"
-EMOJI_KEYWORDS_URL = "https://raw.githubusercontent.com/muan/emojilib/master/emojis.json"
+EMOJI_LIST_URL ||= "http://unicode.org/emoji/charts/full-emoji-list.html"
+EMOJI_KEYWORDS_URL ||= "https://raw.githubusercontent.com/muan/emojilib/master/emojis.json"
 
 # until MS release the emoji flags, we'll use custom made flags
-WINDOWS_FLAGS = Set.new ["1f1e8_1f1f3", "1f1e9_1f1ea", "1f1ea_1f1f8", "1f1eb_1f1f7", "1f1ec_1f1e7", "1f1ee_1f1f9", "1f1ef_1f1f5", "1f1f0_1f1f7", "1f1f7_1f1fa", "1f1fa_1f1f8"]
+WINDOWS_FLAGS ||= Set.new ["1f1e8_1f1f3", "1f1e9_1f1ea", "1f1ea_1f1f8", "1f1eb_1f1f7", "1f1ec_1f1e7", "1f1ee_1f1f9", "1f1ef_1f1f5", "1f1f0_1f1f7", "1f1f7_1f1fa", "1f1fa_1f1f8"]
 
 desc "update emoji images"
 task "emoji:update" => :environment do