updated the docs to reflect the changes made

Author: Chigala

.env.example

@@ -14,12 +14,14 @@ NODE_ENV=development
 # AUTH_GITHUB_CLIENT_ID=
 # AUTH_GITHUB_CLIENT_SECRET=
 
-# Resend is an email service used for signing in to Trigger.dev via a Magic Link.
+# EMAIL VARIABLES.
 # Emails will print to the console if you leave these commented out
-### Visit https://resend.com, create an account and get your API key. Then insert it below along with your From and Reply To email addresses. Visit https://resend.com/docs for more information.
-# RESEND_API_KEY=<api_key>
 # FROM_EMAIL=
 # REPLY_TO_EMAIL=
+# SMTP_HOST= 
+# SMTP_PORT= 
+# SMTP_USER=  
+# SMTP_PASSWORD=  
 
 # CLOUD VARIABLES
 POSTHOG_PROJECT_KEY=

apps/webapp/app/env.server.ts

@@ -27,7 +27,6 @@ const EnvironmentSchema = z.object({
   AUTH_GITHUB_CLIENT_SECRET: z.string().optional(),
   FROM_EMAIL: z.string().optional(),
   REPLY_TO_EMAIL: z.string().optional(),
-  RESEND_API_KEY: z.string().optional(),
   SMTP_HOST: z.string().optional(), 
   SMTP_PORT: z.number().optional(), 
   SMTP_USER: z.string().optional(), 

docs/documentation/guides/self-hosting/flyio.mdx

@@ -82,9 +82,9 @@ Both of these secrets should be set to the base URL of your fly application. For
 
 ![github copy secrets](/images/github-secrets.png)
 
-`RESEND_API_KEY`, `FROM_EMAIL` and `REPLY_TO_EMAIL`
+`FROM_EMAIL`,`REPLY_TO_EMAIL`, `SMTP_HOST`, `SMTP_PORT`, `SMTP_USER` and `SMTP_PASSWORD`
 
-We use [Resend.com](https://resend.com) for email sending (including the magic-link signup/login system). They have a generous free tier of 100 emails a day that should be sufficient. Signup for Resend.com and enter the environment vars below
+We use SMTP for email sending (including the magic-link signup/login system).
 
 ## Set the secrets
 
@@ -99,7 +99,10 @@ fly secrets set \
   APP_ORIGIN="https://<fly app name>.fly.dev" \
   FROM_EMAIL="Acme Inc. <[email protected]>" \
   REPLY_TO_EMAIL="Acme Inc. <[email protected]>" \
-  RESEND_API_KEY=<your API Key> \
+  SMTP_HOST= < your SMTP host > \
+  SMTP_PORT= < your SMTP port > \
+  SMTP_USER=  < your SMTP user > \
+  SMTP_PASSWORD= < your SMTP password > \
   AUTH_GITHUB_CLIENT_ID=<your GitHub OAuth Client ID> \
   AUTH_GITHUB_CLIENT_SECRET=<your GitHUb OAuth Client Secret>