database.rules.json

{
  "rules": {
    "profiles": {
      "$user_id": {
        ".read": "$user_id===auth.uid",
        ".write": "$user_id===auth.uid"
      }
    },
    "rooms": {
      ".read": "auth!=null",
      
        "$community_id":
        {
          ".read": "auth!=null",
          "$room_id": {
        ".read": "auth!=null",
        ".write": "!data.exists() || data.child('admins').child(auth.uid).val()==true",
        "members": {
          ".write": "auth!=null"
        },
          "lastMessage": {
          ".write": "auth!=null"
        }}
         
      }
    },
    "messages": {
      ".read": "auth!=null",
      ".write": "auth!=null",
      ".indexOn": "roomId",
      "$message_id": {
        ".read": "auth!=null",
        ".write": "auth!=null"
      }
    },
    "status": {
      "$user_id": {
        ".read": "auth!=null",
        ".write": "$user_id===auth.uid"
      }
    },
    "requests": {
      ".read": "auth!=null",
      
        "$community_id":
        {
          ".read": "auth!=null",
          "$room_id": {
            ".read": "auth!=null",
            "$req_id": {
              ".read": "auth!=null",
             ".write": "auth!=null"
          }}
         
      }
    },
    ".read": false,
    ".write": false
  }
}