🐛 fix add_custom_word() to use PUT

Author: Ammar Dodin

test/test_speech_to_text_v1.py

@@ -154,7 +154,7 @@ def test_custom_words():
     words_url = 'https://stream.watsonplatform.net/speech-to-text/api/v1/customizations/{0}/words'
     word_url = 'https://stream.watsonplatform.net/speech-to-text/api/v1/customizations/{0}/words/{1}'
 
-    responses.add(responses.POST, word_url.format('custid', 'IEEE'),
+    responses.add(responses.PUT, word_url.format('custid', 'IEEE'),
                   body='{"get response": "yep"}',
                   status=200,
                   content_type='application/json')

watson_developer_cloud/speech_to_text_v1.py

@@ -178,7 +178,7 @@ def add_custom_word(self, customization_id, custom_word):
 
         custom_word_fragment = {'sounds_like': custom_word.sounds_like,
                                 'display_as': custom_word.display_as}
-        return self.request(method='POST',
+        return self.request(method='PUT',
                             url=url.format(customization_id,
                                            custom_word.word),
                             data=json.dumps(custom_word_fragment),