Add models for manual invoicing

Advances #2

added 6 commits

• 7fd94a7f...f8219a49 - 3 commits from branch master
• 8cf2a21d - Add ManualInvoice model
• 5cdeb94e - Merge branch 'master' into 2-add-manual-invoicing
• e3f21a99 - Merge branch 'master' into 2-add-manual-invoicing

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added 4 commits

• e3f21a99...e0e17cec - 2 commits from branch master
• 8f2b3e64 - Merge branch 'master' into 2-add-manual-invoicing
• 12323283 - Re-model manual invoices to use only one Invoice object

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added 3 commits

• 12323283...6fa1899b - 2 commits from branch master
• f3302b2b - Merge branch 'master' into 2-add-manual-invoicing

Compare with previous version

added 7 commits

• f3302b2b...58c824ec - 4 commits from branch master
• 043bc577 - Merge branch 'master' into 2-add-manual-invoicing
• 9ca7fd77 - Remove unused import
• f24130d1 - Fix constraint and add migration for manual invoicing

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marked this merge request as ready

changed title from Resolve "Add manual invoicing" to Add models for manual invoicing

changed the description

merged

mentioned in commit fc51172b