chore(nix): provide cache memcached

shell.nix

@@ -30,6 +30,7 @@ let
         type cleanup_postgres && cleanup_postgres
         type cleanup_widget_memcached && cleanup_widget_memcached
         type cleanup_session_memcached && cleanup_session_memcached
+        type cleanup_cache_memcached && cleanup_cache_memcached
         set +x
       }
 
@@ -87,6 +88,21 @@ let
         set +xe
       fi
 
+      if [[ -z "MEMCACHED_HOST" ]]; then
+        set -xe
+
+        memcached -l localhost -p 11213 &>/dev/null &
+        memcached_pid=$?
+
+        cleanup_session_memcached() {
+          [[ -n "memcached_pid" ]] && kill memcached_pid
+        }
+
+        export MEMCACHED_HOST=localhost MEMCACHED_PORT=11212
+
+        set +xe
+      fi
+
       if [ -n "$ZSH_VERSION" ]; then
         autoload -U +X compinit && compinit
         autoload -U +X bashcompinit && bashcompinit