Fix missing namespace package declaration

GENERATE.md

@@ -2,15 +2,22 @@ Auto-generation instructions
 ============================
 
 1. Set environment variables:
-```
-export GIT_USER_ID=quetz-al
-export GIT_REPO_ID=quetzal-openapi-client
-```
+    ```
+    export GIT_USER_ID=quetz-al
+    export GIT_REPO_ID=quetzal-openapi-client
+    ```
 2. Run auto-generator script `./generate.sh`.
-3. Review changes with `git status`. One file that should be reverted is the `.gitignore`.
-4. Commit/push changes with `./git_push.sh $GIT_USER_ID $GIT_REPO_ID "<your commit message>"`
-5. (Optional) tag a release and push the tag. Use `v` as a prefix:
-```
-git tag -a vX.Y.Z -m "<Some meaningful tag message>"
-git push --tags
-```
+3. Review changes with `git status`.  Take special care of the following files,
+   which have already caused problems in the past:
+
+   * The `.gitignore` file, which is rewritten by the auto-generator.
+   * The `setup.py`, which should have the `namespace_packages=['quetzal']`
+     keyword parameter.
+4. (Optional, can be done manually). Commit/push changes with 
+   `./git_push.sh $GIT_USER_ID $GIT_REPO_ID "<your commit message>"`
+5. (Optional, can be done manually through github) tag a release and push the 
+   tag. Use `v` as a prefix:
+    ```
+    git tag -a vX.Y.Z -m "<Some meaningful tag message>"
+    git push --tags
+    ```

setup.py

@@ -33,6 +33,7 @@
     keywords=["OpenAPI", "OpenAPI-Generator", "Quetzal API"],
     install_requires=REQUIRES,
     packages=find_packages(),
+    namespace_packages=['quetzal'],
     include_package_data=True,
     long_description="""\
     Quetzal: an API to manage data files and their associated metadata.  # noqa: E501