Add CakePHP3 plugin

plugins/cakephp3/cakephp3.plugin.zsh

+# CakePHP 3 basic command completion
+_cakephp3_get_command_list () {
+	cakephp3commands=($(bin/cake completion commands));printf "%s\n" "${cakephp3commands[@]}"
+}
+
+_cakephp3 () {
+  if [ -f bin/cake ]; then
+    compadd `_cakephp3_get_command_list`
+  fi
+}
+
+compdef _cakephp3 bin/cake
+compdef _cakephp3 cake
+
+#Alias
+alias c3='bin/cake'
+
+alias c3cache='bin/cake orm_cache clear'
+alias c3migrate='bin/cake migrations migrate'