Support embedding migrations

Merge pull request #3 from Preciselyco/add-embed-support

add support for reading from embed.fs

v1.4.0

Adds functionality to get the file path from full db dump

v1.3.0

Add support for squashing multiple migration files into one file

v1.2.0

Add support for migrating specified files up or down

v1.1.0

Add support for replacing migrations without executing the migration contents

v1.0.3

Set error code on subcommand failure

v1.0.2

remove inexplicable counting loop, bump version

v1.0.1

api: don't fail if migrations table doesn't exist when dumping schema

v1.0.0

bump version

v0.1.0-beta

cmd, pqmigrate: add configuration help.