Revert "don't flush redis on start, don't delete images on start"

Ah, we did this because heroku.

modules/cache.js

@@ -2,7 +2,7 @@ var config = require("./config");
 var redis = null;
 var fs = require("fs");
 
-// sets up redis connection
+// sets up redis connection, calls clear_cache
 function connect_redis() {
   console.log("connecting to redis...");
   if (process.env.REDISCLOUD_URL) {
@@ -14,6 +14,7 @@ function connect_redis() {
   }
   redis.on("ready", function() {
     console.log("Redis connection established.");
+    clear_cache();
   });
   redis.on("error", function (err) {
     console.error(err);
@@ -25,34 +26,34 @@ function connect_redis() {
 
 
 // flushes redis, deletes faces + helms
-// function clear_cache() {
-//   console.log("Flushing redis");
-//   redis.flushall();
-//   console.log("Deleting all faces + helms...");
-//   fs.readdir(config.faces_dir, function(err, files) {
-//     if (err) {
-//       console.error(err);
-//     } else {
-//       for (var i in files) {
-//         var file = files[i];
-//         if (file[0] != ".") {
-//           // delete face file
-//           fs.unlink(config.faces_dir + file, function(err){
-//             if (err) {
-//               console.error(err);
-//             }
-//           });
-//           // delete helm file, we assume this exists as well
-//           fs.unlink(config.helms_dir + file, function(err){
-//             if (err) {
-//               console.error(err);
-//             }
-//           });
-//         }
-//       }
-//     }
-//   });
-// }
+function clear_cache() {
+  console.log("Flushing redis");
+  redis.flushall();
+  console.log("Deleting all faces + helms...");
+  fs.readdir(config.faces_dir, function(err, files) {
+    if (err) {
+      console.error(err);
+    } else {
+      for (var i in files) {
+        var file = files[i];
+        if (file[0] != ".") {
+          // delete face file
+          fs.unlink(config.faces_dir + file, function(err){
+            if (err) {
+              console.error(err);
+            }
+          });
+          // delete helm file, we assume this exists as well
+          fs.unlink(config.helms_dir + file, function(err){
+            if (err) {
+              console.error(err);
+            }
+          });
+        }
+      }
+    }
+  });
+}
 
 // sets the date of the face file belonging to +hash+ to now
 // the helms file is ignored because we only need 1 file to read/write from