[Feature] Add Postgres data loader (#918)

Co-authored-by: Deven Patel <deven298@yahoo.com>

embedchain/models/data_type.py

@@ -29,6 +29,7 @@ class IndirectDataType(Enum):
     JSON = "json"
     OPENAPI = "openapi"
     GMAIL = "gmail"
+    POSTGRES = "postgres"
 
 
 class SpecialDataType(Enum):
@@ -57,3 +58,4 @@ class DataType(Enum):
     JSON = IndirectDataType.JSON.value
     OPENAPI = IndirectDataType.OPENAPI.value
     GMAIL = IndirectDataType.GMAIL.value
+    POSTGRES = IndirectDataType.POSTGRES.value