README updates.

README.md

@@ -1,6 +1,9 @@
+[![GoDoc](https://godoc.org/lab.pztrn.name/golibs/flagger?status.svg)](https://godoc.org/lab.pztrn.name/golibs/flagger)
+
 # Flagger
 
 Flagger is an arbitrary CLI flags parser, like argparse in Python.
+Flagger is able to parse boolean, integer and string flags.
 
 # Installation
 
@@ -10,4 +13,44 @@ go get -u -v lab.pztrn.name/golibs/flagger
 
 # Usage
 
-//TBW//
+Flagger requires logging interface to be passed on initialization.
+See ``loggerinterface.go`` for required logging functions.
+It is able to run with standart log package, in that case
+initialize flagger like:
+
+```
+flgr = flagger.New(flagger.LoggerInterface(log.New(os.Stdout, "testing logger: ", log.Lshortfile)))
+```
+
+Adding a flag is easy, just fill ``Flag`` structure and pass to ``AddFlag()`` call:
+
+```
+flag_bool := Flag{
+    Name: "boolflag",
+    Description: "Boolean flag",
+    Type: "bool",
+    DefaultValue: true,
+}
+err := flgr.AddFlag(&flag_bool)
+if err != nil {
+    ...
+}
+```
+
+After adding all neccessary flags you should issue ``Parse()`` call to get
+them parsed:
+
+```
+flgr.Parse()
+```
+
+After parsed they can be obtained everywhere you want, like:
+
+```
+val, err := flgr.GetBoolValue("boolflag")
+if err != nil {
+    ...
+}
+```
+
+For more examples take a look at ``flagger_test.go`` file or [at GoDoc](https://godoc.org/lab.pztrn.name/golibs/flagger).