Deployments bug fix #17 (#19)

* Changed the @notempty annotation on the port field of the Deployment entity class to @NotNull and @min.

* Added also the @max annotation to the port field of the Deployment entity class.

src/main/java/org/eclipse/opensmartclide/dbapi/model/Deployment.java

@@ -12,6 +12,8 @@
 
 import javax.validation.constraints.NotEmpty;
 import javax.validation.constraints.NotNull;
+import javax.validation.constraints.Min;
+import javax.validation.constraints.Max;
 import java.util.Date;
 
 @Document(collection = "deployments")
@@ -51,7 +53,9 @@ public class Deployment {
     @NotEmpty
     private String k8s_url;
 
-    @NotEmpty
+    @NotNull
+    @Min(value = 1, message = "Port is a positive integer number (up to 65535).")
+    @Max(value = 65535, message = "Port is a positive integer number (up to 65535).")
     private Integer port;
 
     private Integer replicas;