docs: updates README with labels details and installation

README.adoc

@@ -1,5 +1,27 @@
 = GitHub Changelog Generator
 
-Generates changelog from commits.
+Generates changelog from Pull Requests merged since last release.
 
+[source,bash]
+----
+ghc generate --repository bartoszmajsak/github-changelog-generator
+----
 
+== Labels
+
+Pull Requests will be grouped by labels defined for them. There are two special labels which are handled differently:
+
+ * `skip-changelog` if present on the PR, it will not be included in the list
+ * `dependencies`, if PR is titled `"build(deps): bump lib from X to Y"` will only include latest update in case of many since last release
+
+
+== Installation
+
+Get latest `ghc` binary using simple download script:
+
+[source,bash]
+----
+curl -sL http://git.io/install-ghc | bash
+----
+
+TIP: You can also specify the version and directory before downloading `curl -sL http://git.io/install-ghc | bash -s -- --version=v0.0.1 --dir=~/bin`