Created TROUBLESHOOTING.md file in standard SendGrid format. Added se…

TROUBLESHOOTING.md

@@ -0,0 +1,40 @@
+If you have a non-library SendGrid issue, please contact our [support team](https://support.sendgrid.com).
+
+If you can't find an issue below, please open an [issue](https://github.com/sendgrid/smtpapi-go/issues).
+
+
+## Table of Contents
+ * [Viewing the Request Body](#request-body)
+
+<a name="request-body"></a>
+## Viewing the request body
+
+If you are having issues with the SMTPAPI, or it is not acting in the way you expect,
+viewing the instructions you are sending is a good place to start your troubleshooting.
+
+You can view the headers we are passing to the SendGrid API in the following way.
+
+```golang
+ package main
+
+ import (
+ "fmt"
+ "github.com/sendgrid/smtpapi-go"
+ )
+
+ func main(){
+ //instantiate NewSMTPAPIHeader
+ header := smtapi.NewSMTPAPIHeader()
+
+ //Set some value
+ header.AddCategory("NewUser")
+
+ fmt.Println(header.JSONString()) 
+ }
+ ```
+
+ ```json
+ {"category":["NewUser"]} <nil>
+ ```
+
+ Now you can ensure that your headers add up to your desired behaviour.