Support query process relation metrics (#98)

* Support query process relation metrics
diff --git a/common.graphqls b/common.graphqls
index bb3e0a7..0fd5a03 100644
--- a/common.graphqls
+++ b/common.graphqls
@@ -101,6 +101,7 @@
     ServiceRelation
     ServiceInstanceRelation
     EndpointRelation
+    ProcessRelation
 }
 
 enum DetectPoint {
diff --git a/metrics-v2.graphqls b/metrics-v2.graphqls
index fd426a4..f46f0ca 100644
--- a/metrics-v2.graphqls
+++ b/metrics-v2.graphqls
@@ -36,9 +36,9 @@
 input Entity {
     # 1. scope=All, no name is required.
     # 2. scope=Service, ServiceInstance and Endpoint, set necessary serviceName/serviceInstanceName/endpointName
-    # 3. Scope=ServiceRelation, ServiceInstanceRelation and EndpointRelation
-    #    serviceName/serviceInstanceName/endpointName is/are the source(s)
-    #    destServiceName/destServiceInstanceName/destEndpointName is/are destination(s)
+    # 3. Scope=ServiceRelation, ServiceInstanceRelation, EndpointRelation and ProcessRelation
+    #    serviceName/serviceInstanceName/endpointName/processName is/are the source(s)
+    #    destServiceName/destServiceInstanceName/destEndpointName/destProcessName is/are destination(s)
     #    set necessary names of sources and destinations.
     scope: Scope!
     serviceName: String
@@ -47,12 +47,14 @@
     normal: Boolean
     serviceInstanceName: String
     endpointName: String
+    processName: String
     destServiceName: String
     # Normal service is the service having installed agent or metrics reported directly.
     # Unnormal service is conjectural service, usually detected by the agent.
     destNormal: Boolean
     destServiceInstanceName: String
     destEndpointName: String
+    destProcessName: String
 }
 
 input MetricsCondition {
diff --git a/topology.graphqls b/topology.graphqls
index a8ae8c0..0783e14 100644
--- a/topology.graphqls
+++ b/topology.graphqls
@@ -91,6 +91,14 @@
 type ProcessNode {
     # The process id of each node.
     id: ID!
+    # Service id
+    serviceId: ID!
+    # The literal name of the #serviceId.
+    serviceName: String!
+    # Service Instance id
+    serviceInstanceId: ID!
+    # The literal name of the #serviceInstanceId.
+    serviceInstanceName: String!
     # The name of the process
     name: String!
     # It's a virtual node or real node.