fix typo

README.rst

@@ -63,7 +63,7 @@ Prepare databases::
     dbman prepare -h
 
     # run the standard preparation
-    dbman prepare example/database exemple/tool
+    dbman prepare example/database example/tool
 
 Transfer databases from the working computer to s3 Cloud::
 
@@ -71,7 +71,7 @@ Transfer databases from the working computer to s3 Cloud::
     dbman upload -h
 
     # run the standard transfer
-    dbman upload example/database exemple/tool*
+    dbman upload example/database example/tool*
 
 Transfer databases from s3 Cloud to working computer::
 
@@ -79,7 +79,7 @@ Transfer databases from s3 Cloud to working computer::
     dbman download -h
 
     # run the standard download
-    dbman download example/database exemple/tool*
+    dbman download example/database example/tool*
 
 Delete undesirable databases::