Fix typo.

docker-compose.yml

@@ -180,7 +180,7 @@ services:
       # that if you're using more than 1 instance of Wekan
       # (or any MeteorJS based tool) you're supposed to set
       # MONGO_OPLOG_URL as an environment variable.
-      # Without setting it, Meteor will perform a pull-and-diff
+      # Without setting it, Meteor will perform a poll-and-diff
       # update of it's dataset. With it, Meteor will update from
       # the OPLOG. See here
       #   https://blog.meteor.com/tuning-meteor-mongo-livedata-for-scalability-13fe9deb8908

torodb-postgresql/docker-compose.yml

@@ -173,7 +173,7 @@ services:
       # that if you're using more than 1 instance of Wekan
       # (or any MeteorJS based tool) you're supposed to set
       # MONGO_OPLOG_URL as an environment variable.
-      # Without setting it, Meteor will perform a pull-and-diff
+      # Without setting it, Meteor will perform a poll-and-diff
       # update of it's dataset. With it, Meteor will update from
       # the OPLOG. See here
       #   https://blog.meteor.com/tuning-meteor-mongo-livedata-for-scalability-13fe9deb8908