Update index.js

Added check for duplicate connection names

Author: cemremengu

index.js

@@ -28,7 +28,11 @@ function fastifyPostgres (fastify, options, next) {
     if (!fastify.pg) {
       fastify.decorate('pg', {})
     }
-
+    
+    if (fastify.pg[name]) {
+      next(new Error('Connection name has already been registered: ' + name))
+    }
+    
     fastify.pg[name] = db
   } else {
     if (fastify.pg) {