Merge PR #42: Add notes about setting up dev environment

README.md

@@ -73,4 +73,13 @@ $ relayer --home $RLY q channel ibc1 ibczerochan bank
  quite a bit of user input. The relayer should query to ensure primatives for a counterparty
  chain exist and default to using those first before deciding to create its own.
  It should also create as many of the primatives as possible to random or generated 
- identifiers (hash of chain-ids or chainid-$(rand)).
+ identifiers (hash of chain-ids or chainid-$(rand)).
+
+ ## Setting up Developer Environment
+
+ Working with the relayer can frequently involve working with local developement branches of `gaia`, `cosmos-sdk` and the `relayer`. To setup your environment to point at the local versions of the code and reduce the amount of time in your read-eval-print loops try the following:
+
+ 1. Set `replace github.com/cosmos/cosmos-sdk => /path/to/local/github.com/comsos/cosmos-sdk` at the end of the `go.mod` files for the `relayer` and `gaia`. This will force building from the local versions when running the `./two-chains.sh` script.
+ 2. After `./two-chains.sh` has run, use `go run main.go --home $RLY` for any relayer commands you are working on. This allows you make changes and immediately test them as long as there are no server side changes. 
+ 3. If you make changes in `cosmos-sdk` that need to be reflected server-side, be sure to re-run `./two-chains.sh`.
+ 4. If you need to work off of a `gaia` branch other than `ibc-alpha`, change the branch name at the top of the `./two-chains.sh` script.