Removed unused imports

src/main/java/io/ds/myaktion/domain/Campaign.java

@@ -14,9 +14,6 @@ import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.OneToMany;
 
-import com.fasterxml.jackson.annotation.JsonProperty;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
-
 @Entity
 public class Campaign {