Add the API handler for repositories' tags.

docker_tags_getter/api/v2/tags_api.py

@@ -0,0 +1,28 @@
+class TagsAPI:
+    def __init__(self, fetcher, namespace, repository):
+        self._fetcher = fetcher
+        self._url = f"https://hub.docker.com/v2/namespaces/{namespace}/repositories/{repository}/tags"
+
+    def get_list(self):
+        tags = []
+        number = 1
+
+        while True:
+            page_url = f"{self._url}?page={number}"
+            status, json_data = self._fetcher.get(page_url)
+
+            results = json_data["results"]
+
+            names = list(map(lambda element:element["name"], results))
+            tags += names
+
+            # check for next page
+            next_page = json_data['next']
+
+            if next_page is None:
+                break
+
+            number+=1
+
+        return tags
+