MongoDB/PyMongo: Manifest README as documentation page

doc/adapter/index.md

@@ -6,5 +6,6 @@ mostly for demonstration purposes.
 ```{toctree}
 :maxdepth: 3
 
-rockset
+PyMongo Adapter <pymongo>
+Rockset Adapter <rockset>
 ```

doc/adapter/pymongo.md

@@ -0,0 +1,93 @@
+# PyMongo Adapter for CrateDB
+
+
+## About
+
+[Mongo DB Is Web Scale], CrateDB too. Because CrateDB covers a reasonable
+amount of features of MongoDB, this is an experiment to provide an emulation
+layer for the PyMongo driver, so Python client programs and libraries may
+work unmodified.
+
+
+## What's Inside
+
+An amalgamated [PyMongo] driver, using [CrateDB] as a backend instead of [MongoDB].
+It can run 95% of the [MongoDB "Getting Started" tutorial] successfully.
+
+While coverage of the complete MongoDB API, and more advanced query translations,
+are pretty thin yet, freedom and performance are paramount. There are no [Atlas
+Service Limits] or [MongoDB Limits and Thresholds] in place.
+
+:::{warning}
+**Please note this is pre-alpha software, and is only intended for demonstration
+purposes.**
+<br>
+**Here be dragons. You have been warned.**
+:::
+
+
+## Synopsis
+
+Invoke your PyMongo-based application like this, using `PyMongoCrateDBAdapter`
+to wrap the invocation of `pymongo.MongoClient(...)`, pointing the client to
+a CrateDB database server instead.
+```python
+import pymongo
+from cratedb_toolkit.adapter.pymongo import PyMongoCrateDBAdapter
+
+with PyMongoCrateDBAdapter(dburi="crate://crate@localhost:4200"):
+    client = pymongo.MongoClient("localhost", 27017)
+    collection = client.foo.bar
+
+    inserted_id = collection.insert_one({"author": "Mike", "text": "My first blog post!"}).inserted_id
+    print(inserted_id)
+
+    document = collection.find_one({"author": "Mike"})
+    print(document)
+```
+
+
+## Usage
+
+Install the emulation package.
+```shell
+pip install --upgrade 'cratedb-toolkit[pymongo] @ git+https://github.com/crate-workbench/cratedb-toolkit.git@pymongo-adapter'
+```
+
+Start CrateDB.
+```shell
+docker run --rm -it --name=cratedb \
+  --publish=4200:4200 --publish=5432:5432 \
+  --env=CRATE_HEAP_SIZE=2g crate/crate:nightly \
+  -Cdiscovery.type=single-node
+```
+
+Invoke a Python-based program connecting to MongoDB using the `pymongo`
+package, for example the [Python example program], which is exercising a few
+basic operations.
+
+
+(pymongo-api-coverage)=
+## API Coverage
+
+The most basic primitives: Loading data and querying it back.
+
+- [MongoDB "Getting Started" tutorial]
+
+
+## Examples
+
+To inspect and explore the capabilities of the driver adapter, please use the
+basic [Python example program], and relevant [test cases] of the adapter
+subsystem.
+
+
+[Atlas Service Limits]: https://www.mongodb.com/docs/atlas/reference/atlas-limits/
+[CrateDB]: https://cratedb.com/database
+[MongoDB]: https://www.mongodb.com/products/self-managed/community-edition
+[Mongo DB Is Web Scale]: https://www.youtube.com/watch?v=b2F-DItXtZs
+[MongoDB Limits and Thresholds]: https://www.mongodb.com/docs/manual/reference/limits/
+[MongoDB "Getting Started" tutorial]: https://pymongo.readthedocs.io/en/stable/tutorial.html
+[PyMongo]: https://github.com/mongodb/mongo-python-driver
+[Python example program]: https://github.com/crate-workbench/cratedb-toolkit/blob/main/examples/pymongo_adapter.py
+[test cases]: https://github.com/crate-workbench/cratedb-toolkit/blob/main/tests/adapter/test_pymongo.py