diff --git a/config/environments/development.js.example b/config/environments/development.js.example
index 99871000..231226de 100644
--- a/config/environments/development.js.example
+++ b/config/environments/development.js.example
@@ -9,6 +9,8 @@ var config = {
     ,log_format: '[:date] :req[X-Real-IP] \033[90m:method\033[0m \033[36m:req[Host]:url\033[0m \033[90m:status :response-time ms -> :res[Content-Type]\033[0m'
     ,postgres_auth_user: 'development_cartodb_user_<%= user_id %>'
     ,postgres: {
+        // Parameters to pass to datasource plugin of mapnik
+        // See http://github.com/mapnik/mapnik/wiki/PostGIS
         type: "postgis",
         user: "publicuser",
         host: '127.0.0.1',
diff --git a/config/environments/production.js.example b/config/environments/production.js.example
index 5477b528..a79f9933 100644
--- a/config/environments/production.js.example
+++ b/config/environments/production.js.example
@@ -9,6 +9,8 @@ var config = {
     ,log_format: '[:date] :req[X-Real-IP] \033[90m:method\033[0m \033[36m:req[Host]:url\033[0m \033[90m:status :response-time ms -> :res[Content-Type]\033[0m'
     ,postgres_auth_user: 'cartodb_user_<%= user_id %>'
     ,postgres: {
+        // Parameters to pass to datasource plugin of mapnik
+        // See http://github.com/mapnik/mapnik/wiki/PostGIS
         user: "publicuser",
         host: '127.0.0.1',
         port: 6432,
diff --git a/config/environments/staging.js.example b/config/environments/staging.js.example
index 7904f0d4..8765b73c 100644
--- a/config/environments/staging.js.example
+++ b/config/environments/staging.js.example
@@ -9,6 +9,8 @@ var config = {
     ,log_format: '[:date] :req[X-Real-IP] \033[90m:method\033[0m \033[36m:req[Host]:url\033[0m \033[90m:status :response-time ms -> :res[Content-Type]\033[0m'
     ,postgres_auth_user: 'cartodb_staging_user_<%= user_id %>'
     ,postgres: {
+        // Parameters to pass to datasource plugin of mapnik
+        // See http://github.com/mapnik/mapnik/wiki/PostGIS
         user: "publicuser",
         host: '127.0.0.1',
         port: 6432,
diff --git a/config/environments/test.js.example b/config/environments/test.js.example
index 75fa12fd..63057607 100644
--- a/config/environments/test.js.example
+++ b/config/environments/test.js.example
@@ -9,6 +9,8 @@ var config = {
     ,log_format: '[:date] :req[X-Real-IP] :method :req[Host]:url :status :response-time ms -> :res[Content-Type]'
     ,postgres_auth_user: 'test_cartodb_user_<%= user_id %>'
     ,postgres: {
+        // Parameters to pass to datasource plugin of mapnik
+        // See http://github.com/mapnik/mapnik/wiki/PostGIS
         user: "publicuser",
         host: '127.0.0.1',
         port: 5432,