Removed unused rake task, updated other

As a result only billing rake task remain.

Fixes #8
Merge pull request #9 from dice-cyfronet/create_appl_pdp

Authorization logic moved from ApplianceCreator into cancan
Undefined method capture_message fixed

`sidekiq_retries_exhausted` is not able to invoke normal class method.
As a result "undefined method `capture_message` for
Atmosphere::VmTagsCreatorWorker:Class" was thrown. Fix introduces direct
invocation of `Raven.capture_message`.

To test this behavior I have also upgraded `rspec-sidekiq` into stable
released version 2.0.0

Fixes #11
Merge pull request #12 from dice-cyfronet/fix/vm_tags_raven_message

Undefined method capture_message fixed
Add scripts to creating default devel environment, update documentation, move db seed task to dummy
Merge pull request #10 from dice-cyfronet/tasks

Removed unused rake task, updated other
Add clean developer environment script
check if vm is not created by monitoring

There are situation when between spawning VM on compute site and
registering this machine inside atmosphere DB VM monitoring is triggered.
As a conclusion VM with duplicated `id_at_site` is create, which causes
`Unable to assign VM to appliance` error. Here we are fixing this issue
by checking if VM exists in database or initializing it
(`find_or_initialize`).
Merge pull request #19 from dice-cyfronet/fix/find_or_initialize

check if vm is not created by monitoring
added Atmo prefix to User model class name
fixes multiple default fund assignment problem when saving a user object several times
Added listing of Funds in Admin UI
the fix to the multiple default fund assignment problem
changed default user fund assignment to fire only on create
moved the 4-digit precision fund amount display to a helper
better fund display helper method name
Merge pull request #20 from dice-cyfronet/strange_user_fund_fix

added Atmo prefix to User model class name
do nothing when VM is already deleted

VM tagging is invoked with some delay (when VM should be already seen by
cloud REST API). As a conclusion there can be a situation when VM tagging
is invoked by user already removed selected VM.

Fixes #23
Merge pull request #24 from dice-cyfronet/tags

do nothing when VM is already deleted
Merge pull request #14 from dice-cyfronet/feature_script_to_start_development_environment

Add scripts to creating default devel environment