Added missing experimental SESSION API

Dockerfile

@@ -18,6 +18,7 @@ ENV AUTH=0 \
     POST=0 \
     SECRETS=0 \
     SERVICES=0 \
+    SESSION=0 \
     SWARM=0 \
     SYSTEM=0 \
     TASKS=0 \

README.md

@@ -135,6 +135,7 @@ does not need.
 - `NODES`
 - `PLUGINS`
 - `SERVICES`
+- `SESSION`
 - `SWARM`
 - `SYSTEM`
 - `TASKS`

haproxy.cfg

@@ -59,6 +59,7 @@ frontend dockerfrontend
     http-request deny if { path,url_dec -m reg -i ^(/v[\d\.]+)?/post } ! { env(POST) -m bool }
     http-request deny if { path,url_dec -m reg -i ^(/v[\d\.]+)?/secrets } ! { env(SECRETS) -m bool }
     http-request deny if { path,url_dec -m reg -i ^(/v[\d\.]+)?/services } ! { env(SERVICES) -m bool }
+    http-request deny if { path,url_dec -m reg -i ^(/v[\d\.]+)?/session } ! { env(SESSION) -m bool }
     http-request deny if { path,url_dec -m reg -i ^(/v[\d\.]+)?/swarm } ! { env(SWARM) -m bool }
     http-request deny if { path,url_dec -m reg -i ^(/v[\d\.]+)?/system } ! { env(SYSTEM) -m bool }
     http-request deny if { path,url_dec -m reg -i ^(/v[\d\.]+)?/tasks } ! { env(TASKS) -m bool }