Generating the correct URL for service models

Change-Id: I2b004176b74043f46ee96b0bad4f0659422836da
diff --git a/conf/proxy.js b/conf/proxy.js
index fedbf72..d2459d8 100644
--- a/conf/proxy.js
+++ b/conf/proxy.js
@@ -1,11 +1,13 @@
 const httpProxy = require('http-proxy');
 
+const target = process.env.PROXY || '192.168.46.100';
+
 const proxy = httpProxy.createProxyServer({
-  target: 'http://192.168.46.100:9101'
+  target: `http://${target}:9101`
 });
 
 const extensionsProxy = httpProxy.createProxyServer({
-  target: 'http://192.168.46.100/spa/'
+  target: `http://${target}/spa/`
 });
 
 proxy.on('error', function(error, req, res) {