Fix docs and add caching description.

.gitignore

@@ -16,5 +16,7 @@ target/
 
 dist/
 
+# Cache by reqwest-middleware-cache
+*cache*
 
 logs/

docs/src/SUMMARY.md

@@ -3,11 +3,9 @@
 [Introduction](./introduction.md)
 [Supported Platforms](./supported-platforms.md)
 [Architecture](./architecture.md)
+[Caching](./caching.md)
 [Building](./building.md)
-
+[Developer Log](./developer-log.md)
-## Developer Log
-
-I'm regularly releasing blog posts [on my blog](http://localhost:1313/categories/mapr/).
 
 ## Appendix
 

docs/src/caching.md

@@ -0,0 +1,12 @@
+# Caching
+
+The caching for mapr is handled on the networking layer. This means that data which is fetched over slow IO is cached in
+the format of the network requests. The mapr library is not introducing a separate serialization format for caching.
+
+Instead, caching functionality of HTTP client libraries of the web platform are used. This has the advantage that we can
+honor HTTP headers which configure caching. This is very important for fetched tiles, as they can have an expiry date.
+
+* On the web we are using service workers to cache network requests.
+* On Linux, MacOs, iOS and Android we are
+  utilizing [reqwest-middleware-cache](https://crates.io/crates/reqwest-middleware-cache/), which writes raw network
+  requests to disk.

docs/src/developer-log.md

@@ -0,0 +1,3 @@
+# Developer Log
+
+I'm regularly releasing blog posts [on my blog](https://maxammann.org/categories/mapr/).