Make all aliases optional (a la plugins)

This continues a pattern that was introduced in ffa45b0 and refined
further in later commits.  This enables all aliases by default, but can
be disabled by any user if they remove the appropriate
aliases/enabled/*.bash file.

aliases/available/rails.aliases.bash

@@ -0,0 +1,42 @@
+#!/bin/bash
+
+# Rails Commands
+alias r='rails'
+alias rg='rails g'
+alias rs='rails s'
+alias rc='rails c'
+alias rn='rails new'
+alias rd='rails dbconsole'
+alias rp='rails plugin'
+alias ra='rails application'
+alias rd='rails destroy'
+alias dbm='rake db:migrate'
+
+alias ss='script/server'
+alias ts="thin start"     # thin server
+alias sc='script/console'
+alias restartapp='touch tmp/restart.txt'
+alias restart='touch tmp/restart.txt'  # restart passenger
+alias devlog='tail -f log/development.log'
+alias taild='tail -f log/development.log' # tail dev log
+
+function rails-help() {
+  echo "Rails Aliases Usage"
+  echo
+  echo "  r           = rails"
+  echo "  rg          = rails generate"
+  echo "  rs/ss       = rails server"
+  echo "  ts          = thin server"
+  echo "  rc/sc       = rails console"
+  echo "  rn          = rails new"
+  echo "  rd          = rails dbconsole"
+  echo "  rp          = rails plugin"
+  echo "  ra          = rails application"
+  echo "  rd          = rails destroy"
+  echo "  restartapp  = touch tmp/restart.txt"
+  echo "  restart     = touch tmp/restart.txt"
+  echo "  devlog      = tail -f log/development.log"
+  echo "  taild       = tail -f log/development.log"
+  echo
+}
+