bash tab completion for launcher + discourse-setup (#676)

add tab completion for launcher and discourse-setup.

For launcher, offers command (e.g., rebuild, start) and then offers yml files from containers directory. After that switches (e.g., --run-image) are offered. (Will not offer switches except in final position, sorry.)

discourse-setup offers switches (e.g., --two-container).

discourse-docter has no command line arguments.

scripts/launcher-completion.bash

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+CONTAINER_DIR=$DIR/../containers/
+
+_containers_compgen_filenames() {
+    local cur="$1"
+        compgen -G "$CONTAINER_DIR$cur*.yml"  -- $CONTAINER_DIR"$cur" | xargs  -n 1 basename -s .yml
+    }
+
+_launcher ()
+{
+  local cur
+
+  switches='--skip-prereqs --docker-args --skip-mac-address --run-image'
+  commands='start stop restart destroy enter logs bootstrap run rebuild cleanup start-cmd'
+
+  COMPREPLY=()
+  cur=${COMP_WORDS[COMP_CWORD]}
+
+  case $COMP_CWORD in
+       1)
+          COMPREPLY=( $( compgen -W "$commands" -- $cur ) );;
+       2)
+	  COMPREPLY=( $(_containers_compgen_filenames "$cur") ) ;;
+       *)
+	  COMPREPLY=( $( compgen -W "$switches" -- $cur ) );;
+  esac
+  return 0
+}
+
+_discourse_setup()
+{
+  local cur
+  switches='--debug --skip-rebuild --two-container --skip-connection-test'
+
+  cur=${COMP_WORDS[COMP_CWORD]}
+  COMPREPLY=( $(compgen -W "$switches" -- $cur ) )
+  return 0
+}
+
+complete -F _launcher launcher
+complete -F _launcher ./launcher
+complete -F _discourse_setup discourse-setup
+complete -F _discourse_setup ./discourse-setup