Add Makefile for installing deps and running the tests (#8)

* Add development environment variables to dev.env which is included in Makefile
* Update development instructions in README.md

Author: stumelius

Diff for: Makefile

@@ -0,0 +1,10 @@
+include dev.env
+export
+
+install_deps:
+	pip install -r dev_requirements.txt
+	pip install -r requirements.txt
+	pip install -e .
+
+run_tests:
+	pytest test/integration/athena.dbtspec

Diff for: README.md

@@ -89,15 +89,17 @@ The following features of dbt are not implemented on Athena:
 
 ### Running tests
 
-#### `pytest-dbt-adapter`
-
-* `pip install -r dev_requirements.txt`
-* Set required environmental variables
-  * `DBT_TEST_ATHENA_S3_STAGING_DIR`
-  * `DBT_TEST_ATHENA_REGION`
-  * `DBT_TEST_ATHENA_DATABASE`
-  * `DBT_TEST_ATHENA_SCHEMA`
-* `pytest test/integration/athena.dbtspec`
+First, install the adapter and its dependencies using `make` (see [Makefile](Makefile)):
+
+```bash
+make install_deps
+```
+
+Next, configure the environment variables in [dev.env](dev.env) to match your Athena development environment. Finally, run the tests using `make`:
+
+```bash
+make run_tests
+```
 
 ### Community
 

Diff for: dev.env

@@ -0,0 +1,4 @@
+DBT_TEST_ATHENA_S3_STAGING_DIR=s3://athena-query-results/dbt/
+DBT_TEST_ATHENA_REGION=eu-west-1
+DBT_TEST_ATHENA_DATABASE=awsdatacatalog
+DBT_TEST_ATHENA_SCHEMA=dbt_athena_dev