Add deserialization logic

app/include/fan/Fan.h

@@ -1,9 +1,10 @@
 #ifndef FAN_H_
 #define FAN_H_
 
+#include <Printable.h>
 #include <Serializable.h>
 
-class Fan : public Serializable {
+class Fan : public Serializable, public Printable {
 public:
   virtual void pwm(int percent) = 0;
   virtual int rpm() = 0;

app/include/fan/HwmonFan.h

@@ -18,6 +18,8 @@ public:
 
   json toJson() const override;
 
+  const std::string toString() const override;
+
 private:
   std::shared_ptr<PwmControl> mPwmControl;
   std::shared_ptr<Sensor> mRpmSensor;