Standardize variable namings with plasma-contract

[achiurizo]

We already match variable names closely with plasma-contracts so let's do it for the rest. For example:

elixir-omg	plasma-contracts
owner	output_guard
currency	token
blknum (should be blk_num?)	blkNum
txindex (should be tx_index?)	txIndex
oindex (should be output_index?)	outputIndex

For the latter 3, I've seen some usage where we've mixed between txindex and tx_index on elixir-omg: https://github.com/omisego/elixir-omg/blob/master/apps/omg/lib/omg/state/core.ex#L49 https://github.com/omisego/elixir-omg/blob/master/apps/omg/lib/omg/utxo.ex#L33

[InoMurko]

When it comes to deposits, the emitted event is

elixir-omg	plasma-contracts
owner	depositor
currency	token
blknum (should be blk_num?)	blknum
txindex (should be tx_index?)	txindex
oindex (should be output_index?)	outputindex

[jrhite]

I'm onboard. Do we want to take this all the way down to the DB level (postgres)?

If yes, then DB migration is required.

If no, when we update the ecto models we'll need to up the variable to column name mapping in addition to updating the variable names.

[achiurizo]

I'm onboard. Do we want to take this all the way down to the DB level (postgres)?

I'm :+1: for having it consistent with the DB level.