DOC: Add developer documentation for benchmarking

This commit adds a new file in the developer documentation for how
to run NumPy-Financial's benchmark suite.

Author: Kai-Striega

doc_developer/running_the_benchmarks.md

@@ -0,0 +1,55 @@
+# Running the benchmarks
+
+This document outlines how to setup and run the benchmarks using [asv](https://asv.readthedocs.io/en/v0.6.1/).
+
+## Installing asv
+
+`asv` can be installed with poetry via the `bench` group to install the bench group run:
+
+```shell
+poetry install --with=bench
+```
+
+This will install ``asv`` into your poetry environment.
+
+## Running the benchmarks
+
+To run the benchmarks with ``asv``, simply enter:
+
+```shell
+poetry run asv run
+```
+
+## Viewing the results
+
+There are two steps to viewing the results locally. The results need to be published and the launched in a local web browser.
+
+To publish the results use:
+
+```shell
+poetry run asv publish
+```
+
+And then to view the results:
+
+```shell
+poetry run asv preview
+```
+
+This will launch a local web browser from which you can view the results
+
+## Dry runs
+
+One common use case is to use ``asv`` in development, there are several useful flags that should be used:
+
+```shell
+poetry run asv --python=same --quick --dry-run
+```
+
+We are adding three flags, these flags are:
+
+1. `--python=same` uses the same environment as your development environment (saves time to avoid building environments)
+2. `--quick` only runs the benchmarks once
+3. `--dry-run` to not save the results of the benchmarks
+
+These can be useful for getting quick feedback during development, but should not be used as anything other than a rough guide.