Add example for marker size

Signed-off-by: Knut Ahlers <knut@ahlers.me>

Makefile

@@ -4,4 +4,4 @@ update_example_post:
 	curl -X POST --data-binary @example/postmap.json -o example/postmap.png localhost:5000/map.png
 
 update_example_get:
-	curl -o example/map.png 'localhost:5000/map.png?center=53.5438,9.9768&zoom=15&size=800x500&markers=color:blue|53.54129165,9.98420576699353&markers=color:yellow|53.54565525,9.9680555636958'
+	curl -o example/map.png 'localhost:5000/map.png?center=53.5438,9.9768&zoom=15&size=800x500&markers=color:blue|53.54129165,9.98420576699353&markers=color:yellow|53.54565525,9.9680555636958&markers=size:tiny|color:red|53.54846472989871,9.978977621091543'

README.md

@@ -27,9 +27,10 @@ All map operations are made against the `/map.png` endpoint of the server and ar
     &size=800x500
     &markers=color:blue|53.54129165,9.98420576699353
     &markers=color:yellow|53.54565525,9.9680555636958
+    &markers=size:tiny|color:red|53.54846472989871,9.978977621091543
 ```
 
-The map center is set to a coordinate within Hamburg, Germany with a zoom level of 15. Additionally there are two markers set: One `blue` marker to the Elbphilharmonie, one `yellow` marker to the Hard Rock Cafe Hamburg. The example above (of course without the line breaks) produced this image:
+The map center is set to a coordinate within Hamburg, Germany with a zoom level of 15. Additionally there are two markers set: One `blue` marker to the Elbphilharmonie, one `yellow` marker to the Hard Rock Cafe Hamburg and a `tiny` `red` marker on the St. Michaels church. The example above (of course without the line breaks) produced this image:
 
 ![](example/map.png)
 

example/postmap.json

@@ -18,6 +18,14 @@
         "lat": 53.54565525,
         "lon": 9.9680555636958
       }
+    },
+    {
+      "color": "red",
+      "size": "tiny",
+      "coord": {
+        "lat": 53.54846472989871,
+        "lon": 9.978977621091543
+      }
     }
   ],
   "overlays": [