Fixed user/pass issue for initialization scripts, added docs

docker-entrypoint.sh

@@ -91,16 +91,28 @@ exec_sql() {
 
   echo "running psql command found in: "
   echo $(which psql)
+
+  local user=$DOLTGRES_USER
+  local password=$DOLTGRES_PASSWORD
+
+  # use the default user and pass if not specified in the env
+  if [ -z $user ]; then
+      user="postgres"
+  fi
+
+  if [ -z $password ]; then
+      password="password"
+  fi
   
   while true; do
       if [ -n "$query" ]; then
           set +e
-          output=$(PGPASSWORD=password psql -h 127.0.0.1 -U postgres -c "$query" 2>&1)
+          output=$(PGPASSWORD=$password psql -h 127.0.0.1 -U $user -c "$query" 2>&1)
           status=$?
           set -e
     else
       set +e # tmp disabled to initdb.d/ file err
-      output=$(PGPASSWORD=password psql -h 127.0.0.1 -U postgres < /dev/stdin 2>&1)
+      output=$(PGPASSWORD=$password psql -h 127.0.0.1 -U $user < /dev/stdin 2>&1)
       status=$?
       set -e
     fi
@@ -304,7 +316,6 @@ start_server() {
   db=$(get_env_var "DB")
   export DOLTGRES_USER=$user
   export DOLTGRES_PASSWORD=$password
-  export DOLTGRES_DB=$db
   
   SERVER_PID=-1
 

dockerREADME.md

@@ -102,6 +102,21 @@ For convenience, `POSTGRES_USER` and `POSTGRES_PASSWORD` are accepted as aliases
 To create additional users, connect to the running database and issue `CREATE ROLE` and `GRANT`
 statements as the super-user.
 
+## Initialization
+
+By default, the Doltgres server is initialized with a single empty database with the same name as
+the system user (`postgres` by default). You can add additional data or execute arbitrary SQL setup
+by including initialization scripts in the mounted volume
+`/docker-entrypoint-initdb.d/`. Initialization scripts must have the `.sql` file extension and
+contain statements separated by semicolons. They can be optionally compressed as `.bz2`, `.gz`,
+`.xz`, or `.zst` files with the appropriate extension suffix, e.g. `init.sql.gz`.
+
+Specify an initialization script directory as a volume with `docker run`:
+
+```shell
+$ docker run -v ./init_scripts:/docker-entrypoint-initdb.d/ -p 5432:5432 dolthub/doltgresql:latest
+```
+
 ## Environment Variables
 
 The Doltgres image supports the following environment variables:
@@ -111,5 +126,3 @@ The Doltgres image supports the following environment variables:
   an alias.
 - `DOLTGRES_DATA`: Specifies a path in the container to store database data, created if it doesn't
   exist (default: `/var/lib/doltgresql/`). `PGDATA` is an alias.
-- `DOLTGRES_DB`: Specifies a database name to be created (default: none). The `postgres` database is
-  still created.