doc: added example queries

Signed-off-by: Glenn Vriesman <[email protected]>

README.md

@@ -67,4 +67,29 @@ scrape_configs:
     scrape_interval: 5s
     static_configs:
     - targets: ['f2b-exporter:8080']
-```
+```
+
+## Queries
+You can get the metrics by calling f2b_banned_ip in prometheus.  
+This will return a general unfiltered list of data, which is already usable.
+
+If however, you want to filer the data you can use one of the following filters:
+ * country
+ * currently_banned
+ * jail
+ * geohash
+
+These are some example queries:
+
+#### Total banned ips
+```
+sum(f2b_banned_ip)
+```
+#### Total currently banned ips
+```
+sum(f2b_banned_ip{currently_banned="true"})
+```
+### Total banned ips per country
+```
+sum(f2b_banned_ip) by (country)
+```