Update install.md (#37)

diff --git a/docs/getstarted/install.md b/docs/getstarted/install.md
index 22dd962..4ad1897 100644
--- a/docs/getstarted/install.md
+++ b/docs/getstarted/install.md
@@ -36,6 +36,7 @@
 because by default registry address is 127.0.0.1:30100, 
 just same service center default listen address.
 
+>>curl command read lower case http_proxy environment variable.
 
 ### Run on different infrastructure