Update dapi db connection

README.md

@@ -82,9 +82,9 @@ dir(dapi)
 
 ### Database
 ```python
-import dapi
+from dapi.db import DSDatabase
 
-db = dapi.DSDatabase("ngl")
+db = DSDatabase("ngl")
 sql = 'SELECT * FROM SITE'
 df = db.read_sql(sql)
 print(df)
@@ -135,4 +135,4 @@ The project only works on `Python 3.9` due to AgavePy Issue [#125](https://githu
 
 * Krishna Kumar, University of Texas at Austin
 * Prof. Pedro Arduino, University of Washington
-* Prof. Scott Brandenberg, University of California Los Angeles
+* Prof. Scott Brandenberg, University of California Los Angeles