Generate kallax files with make targets

kallax models should be generated with 'make generate-go',
kallax migrations should be generated with
'MIGRTION_NAME=<name> make generate-migrations' and packed
with 'make pack-migrations'

All the code generation: kallax and vendor can be done
at once with 'make generate'

kallax does not work with go Modules, so it'll be disabled
issue: src-d/go-kallax#296

Signed-off-by: David Pordomingo <David.Pordomingo.F@gmail.com>

.travis.yml

@@ -83,9 +83,9 @@ jobs:
     - name: 'Generated code'
       script:
         - make dependencies
-        - go generate ./...
+        - make generate-go
         - make no-changes-in-commit
-        - kallax migrate --input ./store/models/ --out ./store/migrations --name test-changes
+        - make generate-migrations
         - make no-changes-in-commit
         - make pack-migrations
         - make no-changes-in-commit

Makefile

@@ -42,6 +42,9 @@ LOOKOUT_BIN := $(BIN_PATH)/lookoutd
 ESC_BIN := esc
 TOC_GENERATOR := $(CI_PATH)/gh-md-toc
 
+# Migrations
+MIGRTION_NAME ?= test-changes
+
 .PHONY: pack-migrations
 pack-migrations:
 	chmod -R go=r $(MIGRATIONS_PATH); \
@@ -141,3 +144,18 @@ clean: clean_modcache
 .PHONY: clean_modcache
 clean_modcache:
 	@$(GOCLEAN) -modcache
+
+
+.PHONY: generate
+generate: | generate-go generate-migrations pack-migrations vendor
+
+.PHONY: generate-go
+generate-go:
+	GO111MODULE=off $(GOCMD) generate ./...
+
+.PHONY: generate-migrations
+generate-migrations:
+	GO111MODULE=off kallax migrate \
+		--input ./store/models/ \
+		--out ./store/migrations \
+		--name $(MIGRTION_NAME)

docs/CONTRIBUTING.md

@@ -14,23 +14,37 @@ this project follows the following guidelines.
 
 Before submitting a pull request make sure all the generated code changes are also committed.
 
+To do so, you can generate all needed code and then ensure that nothing is pending to be committed running:
+
+```shell
+$ make dependencies
+$ make generate
+$ make no-changes-in-commit
+```
+
+The output of the last command should be empty if there is nothing pending to be committed.
+
+Otherwise you must commit generated code as produced by the following steps:
+
 
 ### kallax
 
 To generate go code from [kallax](https://github.com/src-d/go-kallax) models, run:
 
 ```shell
-$ go generate ./...
+$ make generate-go
 ```
 
 To update embedded migrations with the new files:
 
 ```shell
-$ make dependencies
-$ kallax migrate --input ./store/models/ --out ./store/migrations --name <name>
+$ MIGRTION_NAME=<name> make generate-migrations
 $ make pack-migrations
 ```
 
+where `<name>` is a short and descriptive name of the purpose of the migration; example: `delete_users_table`
+
+
 ### Dependencies
 
 Go dependencies are managed with [go Modules](https://github.com/golang/go/wiki/Modules). Use `make vendor` to make sure the `vendor` directory is up to date, and commit any necessary changes.