Add a brief explanation.

elifoster · elifoster · commit 0021a032b332 · 2016-04-15T22:19:36.000-07:00
diff --git a/Ruby.gitignore b/Ruby.gitignore
@@ -10,6 +10,7 @@
 /test/version_tmp/
 /tmp/
 
+# Used by dotenv library to load environment variables.
 # .env
 
 ## Specific to RubyMotion:
