Add redis.max configuration setting and document it.

config/environments/development.js.example

@@ -35,6 +35,14 @@ var config = {
     ,redis: {
         host: '127.0.0.1',
         port: 6379,
+        // Max number of connections in each pool.
+        // Users will be put on a queue when the limit is hit.
+        // Set to maxConnection to have no possible queues.
+        // There are currently 3 pools involved in serving
+        // windshaft-cartodb requests so multiply this number
+        // by 3 to know how many possible connections will be
+        // kept open by the server. The default is 50.
+        max: 50,
         idleTimeoutMillis: 1, // idle time before dropping connection
         reapIntervalMillis: 1 // time between cleanups
     }

config/environments/production.js.example

@@ -29,6 +29,14 @@ var config = {
     ,redis: {
         host: '127.0.0.1',
         port: 6379,
+        // Max number of connections in each pool.
+        // Users will be put on a queue when the limit is hit.
+        // Set to maxConnection to have no possible queues.
+        // There are currently 3 pools involved in serving
+        // windshaft-cartodb requests so multiply this number
+        // by 3 to know how many possible connections will be
+        // kept open by the server. The default is 50.
+        max: 50,
         idleTimeoutMillis: 30000, // idle time before dropping connection
         reapIntervalMillis: 1000 // time between cleanups
     }

config/environments/staging.js.example

@@ -28,7 +28,17 @@ var config = {
     }
     ,redis: {
         host: '127.0.0.1',
-        port: 6379
+        port: 6379,
+        // Max number of connections in each pool.
+        // Users will be put on a queue when the limit is hit.
+        // Set to maxConnection to have no possible queues.
+        // There are currently 3 pools involved in serving
+        // windshaft-cartodb requests so multiply this number
+        // by 3 to know how many possible connections will be
+        // kept open by the server. The default is 50.
+        max: 50,
+        idleTimeoutMillis: 30000, // idle time before dropping connection
+        reapIntervalMillis: 1000 // time between cleanups
     }
     ,sqlapi: {
         protocol: 'https',

config/environments/test.js.example

@@ -29,8 +29,16 @@ var config = {
     ,redis: {
         host: '127.0.0.1',
         port: 6333,
-        idleTimeoutMillis: 1,
+        // Max number of connections in each pool.
-        reapIntervalMillis: 1
+        // Users will be put on a queue when the limit is hit.
+        // Set to maxConnection to have no possible queues.
+        // There are currently 3 pools involved in serving
+        // windshaft-cartodb requests so multiply this number
+        // by 3 to know how many possible connections will be
+        // kept open by the server. The default is 50.
+        max: 50,
+        idleTimeoutMillis: 1, // idle time before dropping connection
+        reapIntervalMillis: 1 // time between cleanups
     }
     ,sqlapi: {
         protocol: 'http',