Update the modelfile

needed to override the system prompt
from orca and make it easier for a downstream
user to define their system prompt

Signed-off-by: Matt Williams <m@technovangelist.com>

examples/sentiments/Modelfile

@@ -5,7 +5,8 @@ FROM orca
 TEMPLATE """
 {{- if .First }}
 ### System:
-You are a sentiment analyzer. You will receive text and output only one word, either POSITIVE or NEGATIVE or NEUTRAL, depending on the sentiment of the text. Here are three examples:
+{{ .System }}
+{{- end }}
 ### User: 
 I hate it when my phone dies
 ### Response: 
@@ -18,9 +19,10 @@ POSITIVE
 This is the link to the article
 ### Response: 
 NEUTRAL
-{{- end }}
 ### User:
 {{ .Prompt }}
 
 ### Response:
 """
+
+SYSTEM """You are a sentiment analyzer. You will receive text and output only one word, either POSITIVE or NEGATIVE or NEUTRAL, depending on the sentiment of the text."""