add sql cli and explain it in the readme

capsulflask/cli.py

@@ -0,0 +1,63 @@
+
+import os
+import re
+from datetime import datetime
+
+import click
+from flask.cli import with_appcontext
+from flask import Blueprint
+from psycopg2 import ProgrammingError
+
+from capsulflask.db import get_model, my_exec_info_message
+
+bp = Blueprint('cli', __name__)
+
+@bp.cli.command('sql')
+@click.option('-f', help='script filename')
+@click.option('-c', help='sql command')
+@with_appcontext
+def sql_script(f, c):
+    """Run a sql script against the database. script is run 1 command at a time inside a single transaction."""
+    
+    model = get_model()
+    script = ""
+    if f:
+      filepath = os.path.join(os.getcwd(), f)
+      if not os.path.isfile(filepath):
+        raise f"{filepath} is not a file"
+
+      with open(filepath, 'rb') as file:
+        script = file.read().decode("utf8")
+    elif c:
+      script = c
+    else:
+      click.echo(f"you must provide sql to run either inline with the -c argument or in a file with the -f argument")
+      return
+
+    commands = re.split(";\\s+", script)
+
+    for command in commands:
+      if command.strip() != "":
+
+        model.cursor.execute(command)
+        if re.match("^\\s*select", command, re.IGNORECASE) is not None:
+          for row in model.cursor.fetchall():
+            def format_value(x):
+              if isinstance(x, bool):
+                return "TRUE" if x else "FALSE"
+              if not x :
+                return "null"
+              if isinstance(x, datetime):
+                return x.isoformat()
+              return f"{x}"
+
+            click.echo(", ".join(list(map(format_value, row))))
+        else:
+          click.echo(f"{model.cursor.rowcount} rows affected.")
+
+    model.connection.commit()
+
+@bp.cli.command('cron-task')
+@with_appcontext
+def cron_task():
+  print('a')