cascade account and member deletion
replace 'map' with 'each' because we don't care about the result
replace map with each
Merge branch 'master' into account-deletion
Merge branch 'master' into account-deletion
Added spec for #delete_cascade .
Repair account deletion.
Added spec for atomicity of account deletion.
Transactionalize Account#delete_cascade .
Merge branch 'master' into account-deletion
Merge branch 'master' into account-deletion
Merge branch 'master' into account-deletion
replace delete cascades with SQL functions
MEMBER-DELETE parameter is "username", not "member_id"
Revert "Added spec for atomicity of account deletion."

This reverts commit 20a4ac3f2bd4415b928bf511a8e2e787b388d2c2.
Atomicity is ensured as we are using SQL functions for deletion.