more documentation

docs/00_overview.md

@@ -1,7 +1,13 @@
 # Overview
 
-... some general docs here ...
+Welcome to the Travis API documentation. This is the API used by the official
+[Travis CI](https://next.travis-ci.org) web interface, so everything the web
+interface is able to do is also accomplishable via the API.
 
 ## Media Types
 
 The API is currently [JSON](http://en.wikipedia.org/wiki/JSON) only.
+
+## Clients and Libraries
+
+* **[Travis Ember](https://github.com/travis-ci/travis-ember)**: The official Travis CI client, using [Ember.js](http://emberjs.com/).

lib/travis/api/app/endpoint/artifacts.rb

@@ -2,9 +2,10 @@ require 'travis/api/app'
 
 class Travis::Api::App
   class Endpoint
-    # TODO: Add documentation.
+    # Artifacts are generated by builds. Currently we only expose logs as
+    # artifacts
     class Artifacts < Endpoint
-      # TODO: Add documentation.
+      # Fetches an artifact by it's *id*.
       get('/:id') do |id|
         body service(:artifacts).find_one(params)
       end