How do I add multiple migrations in one version?

[nkurothe]

I want to be able to add multiple migrations in one version, below is a sample

Migrations.add({
version: 1,
name: 'Adds pants to some people in the db.',
up: function() {//code to migrate collection 1 up to version 1}
down: function() {//code to migrate down to version 0}
});

Migrations.add({
version: 1,
name: 'Adds pants to some people in the db.',
up: function() {//code to migrate collection 2 up to version 1}
down: function() {//code to migrate down to version 0}
});

How can I do this? A scenario for this would, we can have multiple people writing migrations, so would want to separate their individual migrations and run them in some order.

[nkurothe]

Duplicates #47