fickit: allow maximal number of connections to MySQL

fickit-backend.yml

@@ -124,6 +124,7 @@ services:
       - MYSQL_RANDOM_ROOT_PASSWORD=yes
     binds:
       - /etc/hosts:/etc/hosts:ro
+      - /etc/mysql/conf.d:/etc/mysql/conf.d:ro
       - /var/lib/fic/mysql:/var/lib/mysql
     net: /run/netns/db
     pid: new
@@ -242,6 +243,11 @@ files:
     source: configs/id_ed25519
     mode: "0400"
 
+  - path: etc/mysql/conf.d/max-conn.cnf
+    contents: |
+      [mysqld]
+      max_connections = 99999
+    mode: "0444"
   - path: etc/iptables/rules.v6
     contents: |
       *filter