Add go:generate example (#56)

examples/go-generate/example.proto

@@ -0,0 +1,16 @@
+syntax = "proto3";
+
+package example;
+
+service Sum {
+  rpc Sum(SumRequest) returns (SumReply) {};
+}
+
+message SumRequest {
+  int32 a = 1;
+  int32 b = 2;
+}
+
+message SumReply {
+  int32 c = 1;
+}