add readme

tests/testthat/sampler/README.md

@@ -0,0 +1,41 @@
+# Demo app
+
+1. Installing R and the the `ts` package
+
+```r
+devtools::install_github("tmelliott/ts")
+```
+
+2. Install node and npm (or pnpm!), then install dependencies
+
+```bash
+pnpm install
+```
+
+3. Build dependencies
+
+```bash
+pnpm build
+```
+
+4. Start Rserve in a separate terminal
+
+```bash
+pnpm rserve
+```
+
+5. Run the app
+
+```bash
+pnpm start
+```
+
+You should see some output in the terminal:
+
+```bash
+Running sampler script...
+
+Mean: 3
+First char: hello
+Sample num: Float64Array(2) [ 4, 3, r_type: 'double_array' ]
+```