Add grunt-config in JS style check.

grunt-config/clean.js

@@ -1,5 +1,7 @@
+'use strict';
+
 module.exports = {
     libs: [
-        "accountant/frontend/static/build"
+        'accountant/frontend/static/build'
     ]
 };

grunt-config/flake8.js

@@ -1,5 +1,7 @@
+'use strict';
+
 module.exports = {
     src: [
         'accountant/**/*.py'
     ]
-}
+};

grunt-config/jscs.js

@@ -7,6 +7,7 @@ module.exports = {
         '<%= paths.frontend_js %>'
     ],
     toolchain: [
-        'Gruntfile.js'
+        'Gruntfile.js',
+        'grunt-config/*.js'
     ]
 };

grunt-config/jshint.js

@@ -7,6 +7,7 @@ module.exports = {
         '<%= paths.frontend_js %>'
     ],
     toolchain: [
-        'Gruntfile.js'
+        'Gruntfile.js',
+        'grunt-config/*.js'
     ]
 };

grunt-config/watch.js

@@ -1,10 +1,15 @@
+'use strict';
+
 module.exports = {
     bower: {
         files: 'bower.json',
         tasks: ['wiredep']
     },
     js: {
-        files: '<%= paths.frontend_js %>',
+        files: [
+            '<%= paths.frontend_js %>',
+            'grunt-config/*.js'
+        ],
         tasks: ['jsdev']
     },
     py: {
@@ -19,7 +24,7 @@ module.exports = {
         tasks: ['htmldev']
     },
     gruntfile: {
-        files: ['Gruntfile.js']
+        files: ['Gruntfile.js', 'grunt-config/*.js']
     },
     requirements: {
         files: ['requirements.txt'],