basic dependencies as per [#85]

modules/poll/config.json

@@ -1,5 +1,6 @@
 {
     "help": "http://github.com/reality/depressionbot/blob/master/modules/poll/README.md",
     "dbKeys": [ "polls" ],
-    "ignorable": true
+    "ignorable": true,
+    "dependencies": [ "users", "command" ]
 }

run.js

@@ -178,7 +178,22 @@ DBot.prototype.reloadModules = function() {
                 // Invalid or no config data
             }
 
-            // Load module config
+            // Shit out if dependencies not met
+            if(_.has(config, 'dependencies')) {
+                var unmetDependencies = _.reduce(config.dependencies, function(memo, dependency) {
+                    if(!_.include(moduleNames, dependency)) {
+                        memo.push(dependency); 
+                    }
+                    return memo;
+                }, [], this);
+
+                if(unmetDependencies.length != 0) {
+                    throw new Error("Dependencies not met: " + unmetDependencies);
+                    return;
+                }
+            }
+
+            // Generate missing DB keys
             this.config[name] = config;
             _.each(config.dbKeys, function(dbKey) {
                 if(!_.has(this.db, dbKey)) {
@@ -186,8 +201,6 @@ DBot.prototype.reloadModules = function() {
                 }
             }, this);
 
-            // Override module config with any stored in the DB
-
             // Load the module itself
             var rawModule = require(moduleDir + name);
             var module = rawModule.fetch(this);