Fix flask invokaction from grunt.

grunt-config/bgShell.js

@@ -1,6 +1,15 @@
+var extend = require('util')._extend;
+
 module.exports = {
     runserver: {
-        cmd: 'python -m manage runserver -d -r',
+        cmd: 'flask run',
+        execOpts: {
+            cwd: '.',
+            env: extend(process.env, {
+                FLASK_APP: 'accountant/__init__.py',
+                FLASK_DEBUG: '1'
+            })
+        },
         fail: true,
         bg: true
     }