add nginx description

plugins/inputs/nginx/README.md

@@ -0,0 +1,50 @@
+# Telegraf Plugin: Nginx
+
+The example plugin gathers metrics about example things
+
+### Configuration:
+
+```
+# Read Nginx's basic status information (ngx_http_stub_status_module)
+[[inputs.nginx]]
+  ## An array of Nginx stub_status URI to gather stats.
+  urls = ["http://localhost/server_status"]
+```
+
+### Measurements & Fields:
+
+- measurement
+    - port 
+    - server
+    - accepts
+    - active
+    - handled
+    - reading
+    - requests
+    - waiting
+
+### Tags:
+
+- All measurements have the following tags:
+    - port
+    - server
+
+### Example Output:
+
+Using this configuration:
+```
+[[inputs.nginx]]
+  ## An array of Nginx stub_status URI to gather stats.
+  urls = ["http://localhost/status"]
+```
+
+When run with:
+```
+./telegraf -config telegraf.conf -input-filter nginx -test
+```
+
+It produces:
+```
+* Plugin: nginx, Collection 1
+> nginx,port=80,server=localhost accepts=605i,active=2i,handled=605i,reading=0i,requests=12132i,waiting=1i,writing=1i 1456690994701784331
+```