rebrand to useSend (#210)

.env.example

@@ -1,4 +1,4 @@
-DATABASE_URL="postgresql://unsend:password@localhost:54320/unsend"
+DATABASE_URL="postgresql://usesend:password@localhost:54320/usesend"
 REDIS_URL="redis://localhost:6379"
 
 
@@ -17,7 +17,7 @@ AWS_SNS_ENDPOINT="http://localhost:3003/api/sns"
 
 NEXTAUTH_SECRET=""
 
-FROM_EMAIL="hello@unsend.dev"
+FROM_EMAIL="hello@usesend.com"
 
 API_RATE_LIMIT=2