Use initial PricePair for assets without feed

[clearloop]

Issue summary

When we add assets without existed feed now after #106, but for deposit asset or other operations of the assets without feed still require PricePair

Other information and links

[mattsse]

This is indeed a feature that we should add, another questions around that issue:

• should we track the latest submission and add a validity period (blocks)? but what should happen if the latest block exceeds this period? freezing the asset in such a case will introduce lots of complications...

[clearloop]

should we track the latest submission and add a validity period (blocks)? but what should happen if the latest block exceeds this period? freezing the asset in such a case will introduce lots of complications...

• Or we force checking if the matched feed has been submitted before adding assets? All PINT stuffs run after chainlink-feed, I think this is weird...

• Embed a submit_feed with default arguments in add_asset is also a solution I think

freezing the asset in such a case will introduce lots of complications...

Agree with this

[clearloop]

This feature has already implemented in #160:

get_price will check the initial_price if feed not exists, it covers most of the calls in PINT which requires feed

I think we should move forward this issue to another which is about:

should we track the latest submission and add a validity period (blocks)? but what should happen if the latest block exceeds this period? freezing the asset in such a case will introduce lots of complications...

[mattsse]

Agreed, but this needs some more research before we can make a decision on this.