Feature: Log files (#423)

* log_file

feature: added a new parameter for crew that creates a txt file to log agent execution

* unit tests and documentation

unit test if file is created but not what is inside the file

src/crewai/utilities/fileHandler.py

@@ -0,0 +1,20 @@
+import os
+from datetime import datetime
+
+
+class FileHandler:
+    """take care of file operations, currently it only logs messages to a file"""
+
+    def __init__(self, file_path):
+        if isinstance(file_path, bool):
+            self._path = os.path.join(os.curdir, "logs.txt")
+        elif isinstance(file_path, str):
+            self._path = file_path
+        else:
+            raise ValueError("file_path must be either a boolean or a string.")
+
+    def log(self, **kwargs):
+        now = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
+        message = f"{now}: ".join([f"{key}={value}" for key, value in kwargs.items()])
+        with open(self._path, "a") as file:
+            file.write(message + "\n")