Support set http proxy for gorush CLI.

only working for GCM protocol.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

gorush/notification_test.go

@@ -542,3 +542,16 @@ func TestCheckAndroidMessage(t *testing.T) {
 	success := PushToAndroid(req)
 	assert.False(t, success)
 }
+
+func TestSetProxyURL(t *testing.T) {
+
+	err := SetProxy("87.236.233.92:8080")
+	assert.Error(t, err)
+	assert.Equal(t, "parse 87.236.233.92:8080: invalid URI for request", err.Error())
+
+	err = SetProxy("a.html")
+	assert.Error(t, err)
+
+	err = SetProxy("http://87.236.233.92:8080")
+	assert.NoError(t, err)
+}