Add RInside Developer Instructions

... see doc/user/RInside.txt

doc/user/RInside.txt

@@ -0,0 +1,51 @@
+Quick guide for developers on getting RInside built
+and installed to integrate with GoldenCheetah
+
+Make sure you have a working GC build already.
+
+1. install R
+
+2. install Rcpp
+
+R> install.packages("Rcpp")
+R> q()
+
+3. install RInside with callback enabled
+
+$ cd ~
+$ mkdir temp
+$ cd temp
+$ git clone https://github.com/eddelbuettel/rinside.git RInside
+$ vi RInside/inst/include/RInsideConfig.h
+
+we use vi, but use an editor of your choice
+uncomment the line from:
+// #define RINSIDE_CALLBACKS
+
+to look like this:
+#define RINSIDE_CALLBACKS
+
+$ R CMD INSTALL RInside
+
+The package is now installed and available to embed
+within GC, so we can now just delete the temp directory
+and contents we just created:
+
+4. cd ..
+5. rm -rf temp
+
+Now we can build GC with R enabled:
+
+6. cd <GoldenCheetah src directory>
+7. vi gcconfig.pri
+
+we use vi, but use an editor of your choice
+add the line:
+
+DEFINES += GC_WANT_R
+
+8. qmake
+9. make
+
+All should be good. If its working help>about>version
+should show the version of R that is embedded.