DOCS: Correct typo

DOCS: Correct typo

gague to gauge

diff --git a/README.md b/README.md
index 84f2c51..4490aa2 100644
--- a/README.md
+++ b/README.md
@@ -577,8 +577,8 @@ Then you can collect the metrics you need on demand:
 
 `‍``ruby
 def metrics
-  user_count_gague = PrometheusExporter::Metric::Gauge.new('user_count', 'number of users in the app')
-  user_count_gague.observe User.count
+  user_count_gauge = PrometheusExporter::Metric::Gauge.new('user_count', 'number of users in the app')
+  user_count_gauge.observe User.count
   [user_count_gauge]
 end
 `‍``

GitHub sha: caaf9990

This commit appears in #122 which was merged by SamSaffron.