feat: add bats tests, docs (#139)

* fix(test): ensure bats file list uses xargs

* docs(readme): use yarn for testing instructions

* fix(test): ensure pipelines fail properly

* docs(alias): fix table header

---------

Signed-off-by: Ismo Vuorinen <ismo@ivuorinen.net>

local/bin/fzf-tmux.md

@@ -0,0 +1,21 @@
+# fzf-tmux
+
+Wrapper around [`fzf`](https://github.com/junegunn/fzf) that opens the
+interface inside a tmux pane or popup.
+
+## Usage
+
+```bash
+fzf-tmux [layout options] [--] [fzf options]
+```
+
+Layout flags like `-p` or `-d` control popup and split behaviour. Use
+`--` to pass arguments directly to `fzf`.
+
+### Example
+
+```bash
+fzf-tmux -p 80%,60% -- --reverse
+```
+
+<!-- vim: set ft=markdown spell spelllang=en_us cc=80 : -->