Add searx user agent to Reddit engine request to comply with API usage terms

searx/engines/reddit.py

 from urllib import urlencode
 from urlparse import urlparse
 from datetime import datetime
+from searx.utils import searx_useragent
 
 # engine dependent config
 categories = ['general', 'images', 'news', 'social media']
                        'limit': page_size})
     params['url'] = search_url.format(query=query)
 
+    # using searx User-Agent
+    params['headers']['User-Agent'] = searx_useragent()
+
     return params
 
 

tests/unit/engines/test_reddit.py

 from searx.engines import reddit
 from searx.testing import SearxTestCase
 from datetime import datetime
+from searx.utils import searx_useragent
 
 
 class TestRedditEngine(SearxTestCase):
         self.assertTrue('url' in params)
         self.assertTrue(query in params['url'])
         self.assertTrue('reddit.com' in params['url'])
+        self.assertEqual(params['headers']['User-Agent'], searx_useragent())
 
     def test_response(self):
         resp = mock.Mock(text='{}')