System prompt at App level (#484)

Co-authored-by: Taranjeet Singh <reachtotj@gmail.com>

embedchain/apps/OpenSourceApp.py

@@ -1,5 +1,5 @@
 import logging
-from typing import Iterable, Union
+from typing import Iterable, Union, Optional
 
 from embedchain.config import ChatConfig, OpenSourceAppConfig
 from embedchain.embedchain import EmbedChain
@@ -18,10 +18,11 @@ class OpenSourceApp(EmbedChain):
     query(query): finds answer to the given query using vector database and LLM.
     """
 
-    def __init__(self, config: OpenSourceAppConfig = None):
+    def __init__(self, config: OpenSourceAppConfig = None, system_prompt: Optional[str] = None):
         """
         :param config: OpenSourceAppConfig instance to load as configuration. Optional.
         `ef` defaults to open source.
+        :param system_prompt: System prompt string. Optional.
         """
         logging.info("Loading open source embedding model. This may take some time...")  # noqa:E501
         if not config:
@@ -33,7 +34,7 @@ class OpenSourceApp(EmbedChain):
         self.instance = OpenSourceApp._get_instance(config.model)
 
         logging.info("Successfully loaded open source embedding model.")
-        super().__init__(config)
+        super().__init__(config, system_prompt)
 
     def get_llm_model_answer(self, prompt, config: ChatConfig):
         return self._get_gpt4all_answer(prompt=prompt, config=config)
@@ -55,7 +56,7 @@ class OpenSourceApp(EmbedChain):
                 "OpenSourceApp does not support switching models at runtime. Please create a new app instance."
             )
 
-        if config.system_prompt:
+        if self.system_prompt or config.system_prompt:
             raise ValueError("OpenSourceApp does not support `system_prompt`")
 
         response = self.instance.generate(