Simplify allowrd DB options for the sandbox

Only allow those compatible with `rails new --database=…` except for
`sqlite` that is transformed to `sqlite3` so it continues to work with
the CircleCI ORB.

Author: elia

lib/solidus_dev_support/templates/extension/bin/sandbox.tt

@@ -3,27 +3,7 @@
 set -e
 test -z "${DEBUG+empty_string}" || set -x
 
-case "$DB" in
-postgres|postgresql)
-  RAILSDB="postgresql"
-  ;;
-mysql)
-  RAILSDB="mysql"
-  ;;
-sqlite3|sqlite)
-  RAILSDB="sqlite3"
-  ;;
-'')
-  echo "~~> Use 'export DB=[postgres|mysql|sqlite]' to control the DB adapter"
-  RAILSDB="sqlite3"
-  ;;
-*)
-  echo "Invalid value specified for the Solidus sandbox: DB=\"$DB\"."
-  echo "Please use 'postgres', 'mysql', or 'sqlite' instead."
-  exit 1
-  ;;
-esac
-echo "~~> Using $RAILSDB as the database engine"
+test "$DB" = "sqlite" && export DB="sqlite3"
 
 if [ -z "$SOLIDUS_BRANCH" ]
 then
@@ -47,7 +27,8 @@ function unbundled {
 }
 
 rm -rf ./sandbox
-unbundled bundle exec rails new sandbox --database="$RAILSDB" \
+unbundled bundle exec rails new sandbox \
+  --database="${DB:-sqlite3}" \
   --skip-bundle \
   --skip-git \
   --skip-keeps \