Allow opt-out of dotfile sourcing (#275)

* allow opt-out of dotfile sourcing

* update README with examples of suppressing environment files

README.md

@@ -183,7 +183,15 @@ Puma-dev supports loading environment variables before puma starts. It checks fo
 * `.powenv`
 * `.pumaenv`
 
-Additionally, puma-dev uses a few environment variables to control how puma is started that you can overwrite in your loaded shell config.
+You can prevent puma-dev from loading any of these environment files by setting a corresponding environment variable to '0':
+
+* `PUMADEV_SOURCE_POWCONFIG=0`
+* `PUMADEV_SOURCE_ENV=0`
+* `PUMADEV_SOURCE_POWRC=0`
+* `PUMADEV_SOURCE_POWENV=0`
+* `PUMADEV_SOURCE_PUMAENV=0`
+
+Additionally, puma-dev uses a few other environment variables to control how puma is started that you can overwrite in your loaded shell config.
 
 * `CONFIG`: A puma configuration file to load, usually something like `config/puma-dev.rb`. Defaults to no config.
 * `THREADS`: How many threads puma should use concurrently. Defaults to 5.

dev/app.go

@@ -236,23 +236,23 @@ func (a *App) Log() string {
 const executionShell = `exec bash -c '
 cd %s
 
-if test -e ~/.powconfig; then
+if test -e ~/.powconfig && [ "$PUMADEV_SOURCE_POWCONFIG" != "0" ]; then
 	source ~/.powconfig
 fi
 
-if test -e .env; then
+if test -e .env && [ "$PUMADEV_SOURCE_ENV" != "0" ]; then
 	source .env
 fi
 
-if test -e .powrc; then
+if test -e .powrc && [ "$PUMADEV_SOURCE_POWRC" != "0" ]; then
 	source .powrc
 fi
 
-if test -e .powenv; then
+if test -e .powenv && [ "$PUMADEV_SOURCE_POWENV" != "0" ]; then
 	source .powenv
 fi
 
-if test -e .pumaenv; then
+if test -e .pumaenv && [ "$PUMADEV_SOURCE_PUMAENV" != "0" ]; then
 	source .pumaenv
 fi