Add list of controls and volume control.

models/control.rb

@@ -2,6 +2,10 @@ require './models/mpd_connection'
 
 class Control
   class << self
+    def controls
+      [:play, :stop, :next, :previous, :pause]
+    end
+
     def play
       MPDConnection.mpd.play
     end
@@ -19,7 +23,11 @@ class Control
     end
 
     def pause
-      MPDConnection.mpd.pause(!MPDConnection.mpd.paused?)
+      MPDConnection.mpd.pause = !MPDConnection.mpd.paused?
+    end
+
+    def volume(value)
+      MPDConnection.mpd.volume = value
     end
   end
 end

mpd_client.rb

@@ -39,6 +39,18 @@ class MPDClient < Sinatra::Base
       JSON Song.queue.map(&:to_h)
     end
 
+    put '/control/:action' do
+      if Control.controls.include?(params[:action].to_sym)
+        Control.send(params[:action])
+      else
+        not_found
+      end
+    end
+
+    put '/control/volume/:value' do
+      Control.volume(params[:value])
+    end
+
   end
 
 end