Issue type:

[x ] question
[ ] bug report
[ x] feature request
[ ] documentation issue

Database system/driver:

[ ] cordova
[ ] mongodb
[ ] mssql
[ ] mysql / mariadb
[ ] oracle
[ x] postgres
[ ] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[ x] latest
[ ] @next
[ ] 0.x.x (or put your version here)

Steps to reproduce or a small repository showing the problem:

Typeorm migrations seems like missing the ability to dry run migrations to look on the sql generated for migrations. This feature is impremented on db-migrate.

It seems similar to the schema:log: Shows sql to be executed by schema:sync command. It shows sql log only for your default connection. To run update queries on a concrete connection use -c option.