Update README.md

README.md

@@ -61,11 +61,18 @@ pkgs <- c("tidyverse", "gratia", "ggplot2",
 install.packages(pkgs)
 ```
 
+RTools or another form of compiler is needed to build compiled packages, particularly if you are on a Windows machine. Visit the [Rtools installation site](https://cran.r-project.org/bin/windows/Rtools/) for more details.
+
 We will be using the latest development version of `mvgam`, as it has several nice features that haven't quite made it to **CRAN** yet. You can install this version using:
 ```r
 devtools::install_github("nicholasjclark/mvgam")
 ```
 
+If the above fails, you can just as easily stick with the **CRAN** version
+```r
+install.packages('mvgam')
+```
+
 ### INSTALLING AND CHECKING STAN
 When working in R, there are two primary interfaces we can use to fit models with Stan (`rstan` and `CmdStan`). Either interface will work, however it is highly recommended that you use the `Cmdstan` backend, with the `{cmdstanr}` interface, rather than using `{rstan}`. More care, however, needs to be taken to ensure you have an up to date version of Stan. **For all `mvgam` functionalities to work properly, please ensure you have at least version 2.29 of Stan installed**. The GitHub development versions of `rstan` and `CmdStan` are currently several versions ahead of this, and both of these development versions are stable. The exact version you have installed can be checked using either `rstan::stan_version()` or `cmdstanr::cmdstan_version()`