modernize bootstrap script

script/bootstrap

@@ -5,12 +5,33 @@ OFF='\033[0m'
 RED='\033[0;31m'
 GREEN='\033[0;32m'
 BLUE='\033[0;34m'
+PURPLE='\033[0;35m'
 
 set -e # Prevent any kind of script failures
 
+# if any of the following env vars are set, use them for the APP_ENV value
+if [ -n "$APP_ENV" ]; then
+  export APP_ENV="$APP_ENV"
+elif [ -n "$ENV" ]; then
+  export APP_ENV="$ENV"
+elif [ -n "$ENVIRONMENT" ]; then
+  export APP_ENV="$ENVIRONMENT"
+elif [ -n "$RAILS_ENV" ]; then
+  export APP_ENV="$RAILS_ENV"
+elif [ -n "$RACK_ENV" ]; then
+  export APP_ENV="$RACK_ENV"
+fi
+
+# set the working directory to the root of the project
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && cd .. && pwd )"
+
+# set the ruby version to the one specified in the .ruby-version file
 [ -z "$RBENV_VERSION" ] && export RBENV_VERSION=$(cat "$DIR/.ruby-version")
+
+# set the app environment to development if it's not set
 [ -z "$APP_ENV" ] && export APP_ENV="development"
+
+# set the path to include the rbenv shims if they exist
 [ -d "/usr/share/rbenv/shims" ] && export PATH=/usr/share/rbenv/shims:$PATH
 
 TRASHDIR=$(mktemp -d /tmp/bootstrap.XXXXXXXXXXXXXXXXX)
@@ -22,11 +43,12 @@ cleanup() {
 trap cleanup EXIT
 
 # Bootstrap gem dependencies.
-echo -e "💎 ${BLUE}Installing Gems...${OFF}"
 if [ "$APP_ENV" == "production" ]; then
-  bundle install --path vendor/gems --local --without development
-  bundle binstubs --all
+  echo -e "💎 ${BLUE}Installing Gems for ${GREEN}production${BLUE}...${OFF}"
+  BUNDLE_WITHOUT=development bundle install --local
+  BUNDLE_WITHOUT=development bundle binstubs --all
 else
-  bundle install --path vendor/gems --local --with development
+  echo -e "💎 ${BLUE}Installing Gems for ${PURPLE}development${BLUE}...${OFF}"
+  bundle install --local
   bundle binstubs --all
-fi
+fi