Adding a dynamic way to include arbitrary dependencies of Wagtail

Dockerfile

@@ -21,8 +21,8 @@ COPY ./wagtail /code/wagtail/
 RUN cd /code/wagtail/ \
     && pip install -e .[testing,docs]
 
-# Install Willow from the host. This folder will be overwritten by a volume mount during run time (so that code
-# changes show up immediately), but it also needs to be copied into the image now so that Willow can be pip install'd.
-COPY ./libs/Willow /code/willow/
-RUN cd /code/willow/ \
-    && pip install -e .[testing]
+# Install Willow and possibly other dependencies from the host. This folder will be overwritten by a volume mount during 
+# run time (so that code changes show up immediately), but it also needs to be copied into the image now so that Willow 
+# can be pip install'd.
+COPY ./libs /code/libs
+RUN cd /code/libs/ && pip install -e $(find * -maxdepth 0 -type d)

README.md

@@ -230,12 +230,14 @@ git remote add upstream git@github.com:wagtail/wagtail.git
 git pull --all
 ```
 
-Contributing to Willow
-----------------------
+Contributing to Willow and other Wagtail dependencies
+-----------------------------------------------------
 
-You can use the same setup to contribute to Willow.
+You can use the same setup to contribute to Willow and other Wagtail dependencies.
 You simply do the same operations to fork the Willow project and point your local copy of Willow to your fork.
 
+You can add dependencies by cloning the repository into the `libs` folder and then rebuild your container.
+The Dockerfile should pick up your library and install it from the local source.
 
 TODO
 ----