README.md in fit4ruby-0.0.2 vs README.md in fit4ruby-0.0.3

@@ -6,9 +6,96 @@
 
 This libary is still work in progress and probably not yet ready to be
 used in your application. However, you are welcome to try it and send
 me comments and patches.
 
+Usage
+-----
+
+You can create an Activity.
+
+```
+require 'fit4ruby'
+
+a = Fit4Ruby::Activity.new
+a.total_timer_time = 30 * 60
+a.new_user_profile({ :age => 33, :height => 1.78, :weight => 73.0,
+                     :gender => 'male', :activity_class => 4.0,
+                     :max_hr => 178 })
+
+a.new_event({ :event => 'timer', :event_type => 'start_time' })
+a.new_device_info({ :device_index => 0 })
+a.new_device_info({ :device_index => 1, :battery_status => 'ok' })
+ts = Time.now
+0.upto(a.total_timer_time / 60) do |mins|
+  ts += 60
+  a.new_record({
+    :timestamp => ts,
+    :position_lat => 51.5512 - mins * 0.0008,
+    :position_long => 11.647 + mins * 0.002,
+    :distance => 200.0 * mins,
+    :altitude => 100 + mins * 0.5,
+    :speed => 3.1,
+    :vertical_oscillation => 9 + mins * 0.02,
+    :stance_time => 235.0 * mins * 0.01,
+    :stance_time_percent => 32.0,
+    :heart_rate => 140 + mins,
+    :cadence => 75,
+    :activity_type => 'running',
+    :fractional_cadence => (mins % 2) / 2.0
+  })
+
+  if mins > 0 && mins % 5 == 0
+    a.new_lap({ :timestamp => ts })
+  end
+end
+a.new_session({ :timestamp => ts })
+a.new_event({ :timestamp => ts, :event => 'recovery_time',
+              :event_type => 'marker',
+              :data => 2160 })
+a.new_event({ :timestamp => ts, :event => 'vo2max',
+              :event_type => 'marker', :data => 52 })
+a.new_event({ :timestamp => ts, :event => 'timer',
+              :event_type => 'stop_all' })
+a.new_device_info({ :timestamp => ts, :device_index => 0 })
+ts += 1
+a.new_device_info({ :timestamp => ts, :device_index => 1,
+                    :battery_status => 'low' })
+ts += 120
+a.new_event({ :timestamp => ts, :event => 'recovery_hr',
+              :event_type => 'marker', :data => 132 })
+```
+
+Now you can have the accumulated data for laps and sessions computed.
+
+```
+a.aggregate
+```
+
+Save it to a file.
+
+```
+Fit4Ruby.write('TEST.FIT', a)
+```
+
+Or read an Activity from a file.
+
+```
+a = Fit4Ruby.read('TEST.FIT')
+```
+
+Then you can access the data in the file.
+
+```
+a.records.each do |r|
+  puts "Latitude: #{r['position_lat']}"
+  puts "Longitude: #{r['position_long']}"
+end
+```
+
+Please see lib/fit4ruby/GlobalFitMessages.rb for the data fields that
+are supported for the various FIT record types.
+
 License
 -------
 
 See [COPYING](COPYING) file.