- Change start-wekan.sh use mongodb port 27018 because xet7 uses

  RocketChat MongoDB at 27017 and Wekan Snap MongoDB at 27019.
  MongoDB 4.0.10 port is installed separately for Xubuntu 19.10
  from MongDB website and changed at /etc/mongod.conf to run
  on port 27018.

Thanks to xet7.

snapcraft.yaml

@@ -1,4 +1,5 @@
 name: wekan
+base: core18
 version: 0
 version-script: git describe --dirty --tags |  cut -c 2-
 summary: The open-source kanban

start-wekan.sh

@@ -7,7 +7,7 @@
       # Debug OIDC OAuth2 etc.
       #export DEBUG=true
       #---------------------------------------------
-      export MONGO_URL='mongodb://127.0.0.1:27019/wekan'
+      export MONGO_URL='mongodb://127.0.0.1:27018/wekan'
       #---------------------------------------------
       # Production: https://example.com/wekan
       # Local: http://localhost:2000