Changes in DB and bugfix

- Dog pic, breed and age are now optional
- Token validation fixed

backend/src/main/java/hu/pazmany/controller/Controller.java

@@ -128,7 +128,7 @@ public class Controller {
 	}
 
 	private boolean isValidToken(String token) {
-		return token == null || !verifyTokenSignature(token);
+		return token != null || verifyTokenSignature(token);
 	}
 
 	private boolean verifyTokenSignature(String token) {

backend/src/main/java/hu/pazmany/jpe/DogEntity.java

@@ -13,14 +13,14 @@ public class DogEntity {
     @Column(name = "name", nullable = false)
     private String name;
 
-    @Column(name = "pic", nullable = false)
+    @Column(name = "pic")
     @Lob
     private byte[] picture;
 
-    @Column(name = "breed", nullable = false)
+    @Column(name = "breed")
     private String breed;
 
-    @Column(name = "age", nullable = false)
+    @Column(name = "age")
     private Integer age;