Add gitlab CI

.gitlab-ci.yml

+image: python:3.5-buster
+
+test:
+    script:
+        - apt update -qy
+        - python3 setup.py
+        - pip install -e .[dev]
+        - python3 -m unittest

setup.py

@@ -23,6 +23,11 @@ setup(
     install_requires=[
         'requests>=2.19.1,<3.0.0'
     ],
+    extras_require={
+        'dev': [
+            'requests-mock'
+        ]
+    },
     classifiers=[
         'Environment :: Web Environment',
         'Intended Audience :: Developers',