Merge pull request alpacahq#237 from alpacahq/bump-version

- bump alpaca-trade-api to v1.2.0
- update pylivetrader version to 0.5.5
- update  pylivetrader docker image to v0.5.5

update version to 0.5.4

Update _version.py

update alpaca-trade-api to 0.51.0

Merge pull request alpacahq#195 from alpacahq/change_can_trade_check

Process pool should be initiated once

update dockerfile to v0.5.0

added comment for migrationo part

update to 0.3.1

minor fixes

when using the combination of config file and pipeline live: set env …

…vars creds

if the credentials are passed using the config file we need somehow to pass then
to pipeline live. this is how