readme update

Author: patrickCNMartin

README.md

@@ -50,8 +50,29 @@ Vesalius has been tested on:
 * Red Hat Enterprise Linux 8.5 (Ootpa)
 
 
-## What's next?
-The Vesalius package is in its early stage of development. We would ask you to
-share with us any bugs, concerns, or features you wish to see implemented.
+
+## Contributing
+
+New interoperablity functions will be added in the near future. Other from
+these quality-of-life functions, no other active development projects are planned. 
+
+If you have any feature you would like to add, please feel free to open a Pull request. The package is still actively maintained.
+
+To faciliate contribution, we recommend using Nix to set up a stable development environment. You can download Nix [here](https://nixos.org/download/). Note that Nix does not run on Windows; you will need to use the Windows Linux Subsytem (WLS) to run nix. Make sure to enable Nix Flakes. 
+
+Once you have Nix installed, clone the current repository and run:
+
+```
+cd vesalius
+nix develop
+```
+
+Nix will derive a reproducible shell environment in which you can proceed with any development you wish. 
+
+==NOTE: Nix is a purely function package manager.== As such, to add new packages, you will need to modify the nix flake by adding your desired package to the `rPackages` list. GitHub packages will need to be added seperately.
+
+Before any pull request, please make sure that your features are covered by the appropriate unit test, are documented using `roxygen2` style comments, and that `R CMD build` and `R CMD check` pass with no warnings or errors. Pull requests will trigger a GitHub `R CMD check` but we would like to minimize the number of times this is triggered. 
+
+## Issues
 
 Please open a GitHub issue or send an email to Patrick Martin (Patrick.Martin@cshs.org)

tests/testthat.R

@@ -1,4 +1,4 @@
 library(testthat)
 library(vesalius)
-usethis::use_package("rlang")
+library(rlang)
 test_check("vesalius")