Change interface of reset_style to read full config from env files

Closes #62
It is highly recommended to invoke reset_styles after upgrade

tools/reset_styles

@@ -8,43 +8,45 @@ var mapnik = require('mapnik');
 var redis = require('redis');
 
 function usage(me, exitcode) {
-  console.log("Usage: " + me + " [--convert] [<target_mapnik_version>]");
+  console.log("Usage: " + me + " [--convert] <environment>");
   process.exit(exitcode);
 }
 
 var doConvert = false;
-var MAPNIK_VERSION;
 
 var node_path = process.argv.shift(); 
 var script_path = process.argv.shift(); 
 var me = path.basename(script_path);
+var ENV;
 var arg;
 while ( arg = process.argv.shift() ) {
   if ( arg == '--convert' ) {
     doConvert = true;
-  } else if ( ! MAPNIK_VERSION ) {
-    MAPNIK_VERSION = arg;
+  }
+  else if ( ! ENV ) {
+    ENV = arg;
   }
   else {
     usage(me, 1);
   }
 }
 
-if ( ! MAPNIK_VERSION ) {
-  MAPNIK_VERSION = mapnik.versions.mapnik;
-}
+if ( ! ENV ) usage(me, 1);
 
-console.log( (doConvert ? "Converting" : "Resetting" ) + ' all styles to target ' + MAPNIK_VERSION);
+global.environment = require('../config/environments/' + ENV);
+var serverOptions = require('../lib/cartodb/server_options'); // _after_ setting global.environment
 
-var REDIS_PORT = 6379; // TODO: make a command line parameter
+var MAPNIK_VERSION = global.environment.mapnik_version || mapnik.versions.mapnik;
+
+console.log( (doConvert ? "Converting" : "Resetting" ) + ' all styles to target ' + MAPNIK_VERSION);
 
 var dbnum = 0;
 
-var mml_store = new grainstore.MMLStore({port:REDIS_PORT}, {mapnik_version:MAPNIK_VERSION});
+var mml_store = new grainstore.MMLStore(serverOptions.redis, serverOptions.grainstore);
 
 var failures = [];
 
-var client = redis.createClient(REDIS_PORT, 'localhost');
+var client = redis.createClient(serverOptions.redis.port, serverOptions.redis.host);
 client.on('connect', function() {
   client.select(dbnum);
   client.keys('map_style|*', function(err, matches) {