add func find session by id

sessionUtils/sessionUtils.go

@@ -34,3 +34,13 @@ var FakeSessions = Sessions{
 		},
 	},
 }
+
+func FindSessionByID(sessionId string, sessions []Session) Session {
+	for _, session := range sessions {
+		if session.SessionId == sessionId {
+			return session
+		}
+	}
+	var temp Session = Session{}
+	return temp
+}