Add more tickers to Redis and/or delete obsolete tickers

[sodogemuchwow]

@tomcounsell where can I see a list of all the tickers for which we are currently saving price and TA data?
We have data for some tickers that hasn't been refreshed for almost a year, perhaps consider deleting it?

For example,

INFO:settings:For key b'OMG_BTC:binance:PriceStorage:low_price', last entry is at 2018/02/07 23:30:00 UTC (b'141100:116058.0')
INFO:settings:For key b'LTC_BTC:binance:PriceStorage:high_price', last entry is at 2018/02/07 23:30:00 UTC (b'1813199:116058.0')

Use

python manage.py get_indicator_status --ticker=...

to see these logs.