Add README

README.md

@@ -1,21 +1,31 @@
 # Tilastokeskus
 
-**TODO: Add description**
+Tilastokeskus (also the name of an unrelated Finnish government agency) is a minimal analytics
+tool written in Elixir, using Raxx, and PostgreSQL storage. It is currently in early development,
+but I use it for my own sites.
 
-## Installation
+The point of Tilastokeskus is to replace Google Analytics on my own sites, but as I use very few
+features from GA, the features in Tilastokeskus are also minimal. The motivation for writing my
+own analytics tool was to 1) have 1st party analytics, 2) get rid of GA, 3) learn Raxx.
 
-If [available in Hex](https://hex.pm/docs/publish), the package can be installed
-by adding `tilastokeskus` to your list of dependencies in `mix.exs`:
+## Currently implemented features
 
-```elixir
-def deps do
-  [
-    {:tilastokeskus, "~> 0.1.0"}
-  ]
-end
-```
+* Collection of data and storing to PostgreSQL
+* Full referrers with and without queries + domains
+* Simple session system with cookie to group one session's requests
+* Parsing of UA with ua_detector library
+* GeoIP with autoupdated MaxMind databases
+* Support for allowing a set of hostnames and forbidding others
+* Autoremoval of sensitive data with configurable interval
 
-Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
-and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
-be found at [https://hexdocs.pm/tilastokeskus](https://hexdocs.pm/tilastokeskus).
+## Future features
 
+* UI with different graphs to visualize data
+* Realtime view to show users currently on site
+* Take DNT header into account somehow
+
+## Won't be implemented (out of scope)
+
+* User accounts/authentication (use HTTP basic auth or SSH tunneling or something else)
+* Integrations to 3rd party systems
+* Invasive tracking (Flash cookies, dirty tricks)