Fixed an error in Jackson Parse.

Was receiving the following error so added _id and getter and setter for it:

com.cribbstechnologies.clients.mandrill.exception.RequestFailedException: Json Mapping Exception
        at com.cribbstechnologies.clients.mandrill.request.MandrillRESTRequest.performPostRequest(MandrillRESTRequest.java:82)
        at com.cribbstechnologies.clients.mandrill.request.MandrillRESTRequest.postRequest(MandrillRESTRequest.java:37)
        at com.cribbstechnologies.clients.mandrill.request.MandrillMessagesRequest.sendMessage(MandrillMessagesRequest.java:32)
        at com.memmee.util.MemmeeMailSenderImpl.sendForgotPasswordEmail(MemmeeMailSenderImpl.java:84)
        at com.memmee.UserResource.forgotPassword(UserResource.java:213)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
        at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$VoidOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:167)
        at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
        at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
        at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
        at com.sun.jersey.server.impl.uri.rules.ResourceObjectRule.accept(ResourceObjectRule.java:100)
        at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
        at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1480)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1411)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1360)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1350)
        at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
        at com.yammer.dropwizard.jetty.NonblockingServletHolder.handle(NonblockingServletHolder.java:47)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1331)
        at com.yammer.dropwizard.servlets.ThreadNameFilter.doFilter(ThreadNameFilter.java:29)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1302)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:448)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1067)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:377)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1001)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:129)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
        at com.yammer.metrics.jetty.InstrumentedHandler.handle(InstrumentedHandler.java:200)
        at org.eclipse.jetty.server.handler.GzipHandler.handle(GzipHandler.java:233)
        at com.yammer.dropwizard.jetty.BiDiGzipHandler.handle(BiDiGzipHandler.java:123)
        at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
        at org.eclipse.jetty.server.Server.handle(Server.java:360)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:454)
        at org.eclipse.jetty.server.BlockingHttpConnection.handleRequest(BlockingHttpConnection.java:47)
        at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:890)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:944)
        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:630)
        at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:230)
        at org.eclipse.jetty.server.BlockingHttpConnection.handle(BlockingHttpConnection.java:66)
        at org.eclipse.jetty.server.nio.BlockingChannelConnector$BlockingChannelEndPoint.run(BlockingChannelConnector.java:293)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:603)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:538)
        at java.lang.Thread.run(Thread.java:680)
Caused by: org.codehaus.jackson.map.exc.UnrecognizedPropertyException: Unrecognized field "_id" (Class com.cribbstechnologies.clients.mandrill.model.response.message.MessageResponse), not marked as ignorable